Sugarcane aphid resistant sorghums found within USDA-ARS Lubbock, TX genotypes

USDA-ARS?s Scientific Manuscript database

The sugarcane aphid, Melanaphis sacchari, was discovered infesting grain sorghum in the southern United States in 2013 and has been a perennial pest through 2016. We evaluated 25 sorghum genotypes in a search for host plant resistance to this pest. Plants were started from seed (N = 16 replication...

Registration of Tx3410 through Tx3428 sorghum germplasm resistant to sugarcane aphid [Melanaphis sacchari (Zehntner)

USDA-ARS?s Scientific Manuscript database

The sugarcane aphid [Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae)] became virulent on sorghum in the United States in 2013. By 2015 the aphid was identified in 400 counties in 17 states accounting for 97% of hectares and 98% of production in the U.S. In 2014 and 2015, the estimated econom...

First report of Sugarcane yellow leaf virus infecting Columbus Grass (Sorghum almum) in Florida

USDA-ARS?s Scientific Manuscript database

Sugarcane yellow leaf virus (SCYLV) [genus Polerovirus, family Luteoviridae] is the causal agent of sugarcane yellow leaf disease. SCYLV is widespread in Florida where sugarcane was the only known natural host of this virus. During spring 2015, we collected (leaves or stalks) and tested several gras...

Status of Sugarcane yellow leaf virus and its impact in different progenies

USDA-ARS?s Scientific Manuscript database

Yellow leaf disease caused by Sugarcane yellow leaf virus (SCYLV) a Polerovirus is an important disease for sugarcane industries worldwide. High yield losses up to 50% were reported in susceptible varieties. Most of the commercial cultivars in Florida are infected with SCYLV; therefore, there is a ...

Identification of three genotypes of sugarcane yellow leaf virus causing yellow leaf disease from India and their molecular characterization.

PubMed

Viswanathan, R; Balamuralikrishnan, M; Karuppaiah, R

2008-12-01

Sugarcane yellow leaf virus (SCYLV) that causes yellow leaf disease (YLD) in sugarcane (recently reported in India) belongs to Polerovirus. Detailed studies were conducted to characterize the virus based on partial open reading frames (ORFs) 1 and 2 and complete ORFs 3 and 4 sequences in their genome. Reverse-transcriptase polymerase chain reaction (RT-PCR) was performed on 48 sugarcane leaf samples to detect the virus using a specific set of primers. Of the 48 samples, 36 samples (field samples with and without foliar symptoms) including 10 meristem culture derived plants were found to be positive to SCYLV infection. Additionally, an aphid colony collected from symptomatic sugarcane in the field was also found to be SCYLV positive. The amplicons from 22 samples were cloned, sequenced and acronymed as SCYLV-CB isolates. The nucleotide (nt) and amino acid (aa) sequence comparison showed a significant variation between SCYLV-CB and the database sequences at nt (3.7-5.1%) and aa (3.2-5.3%) sequence level in the CP coding region. However, the database sequences comprising isolates of three reported genotypes, viz., BRA, PER and REU, were observed with least nt and aa sequence dissimilarities (0.0-1.6%). The phylogenetic analyses of the overlapping ORFs (ORF 3 and ORF 4) of SCYLV encoding CP and MP determined in this study and additional sequences of 26 other isolates including an Indian isolate (SCYLV-IND) available from GenBank were distributed in four phylogenetic clusters. The SCYLV-CB isolates from this study lineated in two clusters (C1 and C2) and all the other isolates from the worldwide locations into another two clusters (C3 and C4). The sequence variation of the isolates in this study with the database isolates, even in the least variable region of the SCYLV genome, showed that the population existing in India is significantly different from rest of the world. Further, comparison of partial sequences encoding for ORFs 1 and 2 revealed that YLD in sugarcane in

Biology and management of sugarcane yellow leaf virus: an historical overview.

PubMed

ElSayed, Abdelaleim Ismail; Komor, Ewald; Boulila, Moncef; Viswanathan, Rasappa; Odero, Dennis C

2015-12-01

Sugarcane yellow leaf virus (SCYLV) is one of the most widespread viruses causing disease in sugarcane worldwide. The virus has been responsible for drastic economic losses in most sugarcane-growing regions and remains a major concern for sugarcane breeders. Infection with SCYLV results in intense yellowing of the midrib, which extends to the leaf blade, followed by tissue necrosis from the leaf tip towards the leaf base. Such symptomatic leaves are usually characterized by increased respiration, reduced photosynthesis, a change in the ratio of hexose to sucrose, and an increase in starch content. SCYLV infection affects carbon assimilation and metabolism in sugarcane, resulting in stunted plants in severe cases. SCYLV is mainly propagated by planting cuttings from infected stalks. Phylogenetic analysis has confirmed the worldwide distribution of at least eight SCYLV genotypes (BRA, CHN1, CHN3, CUB, HAW, IND, PER, and REU). Evidence of recombination has been found in the SCYLV genome, which contains potential recombination signals in ORF1/2 and ORF5. This shows that recombination plays an important role in the evolution of SCYLV.

Pepo aphid-borne yellows virus: a new species in the genus Polerovirus.

PubMed

Ibaba, Jacques D; Laing, Mark D; Gubba, Augustine

2017-02-01

Pepo aphid-borne yellows virus (PABYV) has been proposed as a putative representative of a new species in the genus Polerovirus in the family Luteoviridae. The genomes of two South African (SA) isolates of cucurbit-infecting PABYV were described in this record. Total RNA, extracted from a pattypan (Cucurbita pepo L.) and a baby marrow (C. pepo L.) leaf samples, was subjected to next-generation sequencing (NGS) on the HiSeq Illumina platform. Sanger sequencing was subsequently used to authenticate the integrity of PABYV's genome generated from de novo assembly of the NGS data. PABYV genome of SA isolates consists of 5813 nucleotides and displays an organisation typical of poleroviruses. Genome sequence comparisons of the SA PABYV isolates to other poleroviruses support the classification of PABYV as a new species in the genus Polerovirus. Recombination analyses showed that PABYV and Cucurbit aphid-borne yellows virus (CABYV) shared the same ancestor for the genome part situated between breaking points. Phylogenetic analyses of the RNA-dependent RNA polymerase and the coat protein genes showed that SA PABYV isolates shared distant relationship with CABYV and Suakwa aphid-borne yellows virus. Based on our results, we propose that PABYV is a distinct species in the genus Polerovirus.

Antibiosis and tolerance discovered in USDA-ARS sorghums resistant to the sugarcane aphid Melanaphis sacchari (Hemiptera: Aphididae)

USDA-ARS?s Scientific Manuscript database

The sugarcane aphid, Melanaphis sacchari, was discovered infesting grain sorghum near Beaumont, TX, close to the Texas and Louisiana state line a few miles inland from the Gulf coast in the late summer of 2013, and has been a perennial pest of sorghum through 2016. Our research was aimed at identif...

Unravel the genetic basis of Sugarcane Yellow Leaf Virus (SCYLV) resistance in Saccharum spp. hybrid

USDA-ARS?s Scientific Manuscript database

Sugarcane (Saccharum Spp.) produces 80% of the world’s table sugar along with several other byproducts. The production of sugarcane is vulnerable due to infestation of sugarcane yellow leaf virus (SCYLV) worldwide. A genetic mapping study was conducted using an F1 segregating population derived from...

Survey of aphid population in a yellow passion fruit crop and its relationship on the spread Cowpea aphid-borne mosaic virus in a subtropical region of Brazil.

PubMed

Garcêz, Renata Maia; Chaves, Alexandre Levi Rodrigues; Eiras, Marcelo; Meletti, Laura Maria Molina; de Azevedo Filho, Joaquim Adelino; da Silva, Leonardo Assis; Colariccio, Addolorata

2015-01-01

Passion fruit woodiness may be caused by Cowpea aphid-borne mosaic virus (CABMV) and is currently the major passion fruit disease in Brazil. To assess the virus-vector-host interactions, a newly introduced golden passion fruit plantation located in eastern region of São Paulo State, Brazil, was monitored. Dissemination of CABMV was determined analyzing golden passion fruit plants monthly for 18 months by PTA-ELISA. Seasonality and aphid fauna diversity was determined by identification of the captured species using yellow sticky, yellow water-pan and green tile traps. Population composition of the aphid species was determined using the descriptive index of occurrence, dominance and general classification and overlap of species in the R program. Analyses of species grouping afforded to recognize 14 aphid species. The genus Aphis represented 55.42 % of the species captured. Aphid species formed two distinct clusters, one of which was characterized by the diversity of polyphagous species that presented high potential to spread CABMV. The low abundance and diversity of aphid species did not interfere negatively in the CABMV epidemiology. The genus Aphis, particularly Aphis fabae/solanella and A. gossypii, was crucial in the spread of CABMV in passion fruit orchards in the eastern State of São Paulo.

First Complete Genome Sequence of Suakwa aphid-borne yellows virus from East Timor

PubMed Central

Maina, Solomon; Edwards, Owain R.; de Almeida, Luis; Ximenes, Abel

2016-01-01

We present here the first complete genomic RNA sequence of the polerovirus Suakwa aphid-borne yellows virus (SABYV), from East Timor. The isolate sequenced came from a virus-infected pumpkin plant. The East Timorese genome had a nucleotide identity of 86.5% with the only other SABYV genome available, which is from Taiwan. PMID:27469955

Soybean aphids making their summer appearance early

USDA-ARS?s Scientific Manuscript database

Two small, soft-bodied insects have begun showing up in South Dakota soybean. One is the soybean aphid, and the other is a mealybug. Soybean aphids are yellow to yellow/green and are usually found feeding on the underside of leaves. Incidence of soybean aphid has been a bit higher than typical fo...

Sugarcane Aphid Population Growth, Plant Injury, and Natural Enemies on Selected Grain Sorghum Hybrids in Texas and Louisiana.

PubMed

Brewer, Michael J; Gordy, John W; Kerns, David L; Woolley, James B; Rooney, William L; Bowling, Robert D

2017-10-01

In response to the 2013 outbreak of sugarcane aphid, Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae), on sorghum, Sorghum bicolor (L.), in North America, experiments were conducted at three southern U.S. grain sorghum production locations (Corpus Christi, TX; Winnsboro, LA; Rosenberg, TX). The objectives were to authenticate yield decline on susceptible hybrids (2014 and 2015) and to measure aphid population growth and natural enemy prevalence on susceptible and resistant hybrids with similar genetic background (2014). Yield decline on susceptible hybrids (Tx 2752/Tx430 and DKS53-67) was more substantial when aphid population growth accelerated quickly and peaked above 300 aphids per leaf (50 to nearly 100% yield decline). Location and year variation in maximum aphid density and cumulative aphid-days was high, with doubling time values on the susceptible hybrids ranging between 3.9 and 7.9 d. On resistant Tx2752/Tx2783, leaf injury and yield decline were not seen or less severe than on its paired susceptible Tx2752/Tx430. Aphids declined on Tx2752/Tx2783 after initial colony establishment (Corpus Christi) or took about 60% longer to double in population size when compared with Tx2572/Tx430 (Winnsboro). The predominant natural enemy taxa were aphelinid mummies (Hymenoptera: Aphelinidae), ladybird beetles (Coleoptera: Coccinellidae), and sryphid flies (Diptera: Syrphidae), and they were more prevalent during flowering than prior to flowering. They were generally responsive to changes in aphid density of both susceptible and resistant hybrids, but variability points to need for further study. In future research, full season observations should continue as well as more detailed study of potential compatibility of sorghum resistance and biological control. © The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Microsatellite markers reveal a predominant sugarcane aphid (Homoptera: Aphididae) clone is found on sorghum in seven states and one territory of the USA

USDA-ARS?s Scientific Manuscript database

The sugarcane aphid, Melanaphis sacchari, has become a serious pest causing severe economic losses to sorghum grown in the southern United States (U.S.). Since its original detection in four states in 2013, M. sacchari on sorghum has now, for 2016, spread to 19 states. The presence of one or multip...

Resistance to Cucurbit aphid-borne yellows virus in Melon Accession TGR-1551.

PubMed

Kassem, Mona A; Gosalvez, Blanca; Garzo, Elisa; Fereres, Alberto; Gómez-Guillamón, Maria Luisa; Aranda, Miguel A

2015-10-01

The genetic control of resistance to Cucurbit aphid-borne yellows virus (CABYV; genus Polerovirus, family Luteoviridae) in the TGR-1551 melon accession was studied through agroinoculation of a genetic family obtained from the cross between this accession and the susceptible Spanish cultivar 'Bola de Oro'. Segregation analyses were consistent with the hypothesis that one dominant gene and at least two more modifier genes confer resistance; one of these additional genes is likely present in the susceptible parent 'Bola de Oro'. Local and systemic accumulation of the virus was analyzed in a time course experiment, showing that TGR-1551 resistance was expressed systemically as a significant reduction of virus accumulation compared with susceptible controls, but not locally in agroinoculated cotyledons. In aphid transmission experiments, CABYV inoculation by aphids was significantly reduced in TGR-1551 plants, although the virus was acquired at a similar rate from TGR-1551 as from susceptible plants. Results of feeding behavior studies using the DC electrical penetration graph technique suggested that viruliferous aphids can salivate and feed from the phloem of TGR-1551 plants and that the observed reduction in virus transmission efficiency is not related to reduced salivation by Aphis gossypii in phloem sieve elements. Since the virus is able to accumulate to normal levels in agroinoculated tissues, our results suggest that resistance of TGR-1551 plants to CABYV is related to impairment of virus movement or translocation after it reaches the phloem sieve elements.

Invasion of sorghum in the Americas by a new sugarcane aphid (Melanaphis sacchari) superclone.

PubMed

Nibouche, Samuel; Costet, Laurent; Holt, Jocelyn R; Jacobson, Alana; Pekarcik, Adrian; Sadeyen, Joëlle; Armstrong, J Scott; Peterson, Gary C; McLaren, Neal; Medina, Raul F

2018-01-01

In the United States (US), the sugarcane aphid (SCA) Melanaphis sacchari (Zehnter) (Hemiptera: Aphididae) was introduced in the 1970s, however at that time it was only considered a pest of sugarcane. In 2013, a massive outbreak of M. sacchari occured on sorghum, resulting in significant economic damage to sorghum grown in North America including the US, Mexico, and Puerto Rico. The aim of the present study was to determine if the SCA pest emergence in American sorghum resulted from the introduction of new genotypes. To this end we used microsatellite markers and COI sequencing to compare the genetic diversity of SCA populations collected in the Americas after the 2013 SCA outbreak on sorghum (during 2013-2017) to older samples collected before the pest outbreak (during 2007-2009). Our results show that the SCA outbreak in the Americas and the Caribbean observed since 2013 belong to populations exhibiting low genetic diversity and consisting of a dominant clonal lineage, MLL-F, which colonizes Sorghum spp. and sugarcane. The comparison of MLL-F specimens collected post-2013 with specimens collected in Louisiana in 2007 revealed that both populations are genetically distinct, according to COI sequencing and microsatellite data analyses. Our result suggest that MLL-F is a new invasive genotype introduced into the Americas that has spread rapidly across sorghum growing regions in the US, Mexico, Honduras and the Caribbean. The origin of this introduction is either Africa or Asia, with Asia being the most probable source.

Aphids capable of fine resolution landing

USDA-ARS?s Scientific Manuscript database

Aphids vector many devastating plant viruses, including the non-persistent papaya ringspot virus (PRSV), which reduces yield in both cucurbits and papaya. It has been demonstrated that some aphids are more attracted to colors symptomatic of virus infection, especially yellow. However, alate aphids a...

Molecular characterization and phylogenetic analysis of Sugarcane yellow leaf virus isolates from China.

PubMed

Gao, San-Ji; Lin, Yi-Hua; Pan, Yong-Bao; Damaj, Mona B; Wang, Qin-Nan; Mirkov, T Erik; Chen, Ru-Kai

2012-10-01

Sugarcane yellow leaf virus (SCYLV) (genus Polerovirus, family Luteoviridae), the causal agent of sugarcane yellow leaf disease (YLD), was first detected in China in 2006. To assess the distribution of SCYLV in the major sugarcane-growing Chinese provinces, leaf samples from 22 sugarcane clones (Saccharum spp. hybrid) showing YLD symptoms were collected and analyzed for infection by the virus using reverse transcription PCR (RT-PCR), quantitative RT-PCR, and immunological assays. A complete genomic sequence (5,879 nt) of the Chinese SCYLV isolate CHN-FJ1 and partial genomic sequences (2,915 nt) of 13 other Chinese SCYLV isolates from this study were amplified, cloned, and sequenced. The genomic sequence of the CHN-FJ1 isolate was found to share a high identity (98.4-99.1 %) with those of the Brazilian (BRA) genotype isolates and a low identity (86.5-86.9 %) with those of the CHN1 and Cuban (CUB) genotype isolates. The genetic diversity of these 14 Chinese SCYLV isolates was assessed along with that of 29 SCYLV isolates of worldwide origin reported in the GenBank database, based on the full or partial genomic sequence. Phylogenetic analysis demonstrated that all the 14 Chinese SCYLV isolates clustered into one large group with the BRA genotype and 12 other reported SCYLV isolates. In addition, five reported Chinese SCYLV isolates were grouped with the Peruvian (PER), CHN1 and CUB genotypes. We therefore speculated that at least four SCYLV genotypes, BRA, PER, CHN1, and CUB, are associated with YLD in China. Interestingly, a 39-nt deletion was detected in the sequence of the CHN-GD3 isolate, in the middle of the ORF1 region adjacent to the overlap between ORF1 and ORF2. This location is known to be one of the recombination breakpoints in the Luteoviridae family.

Determining seed transmission of sugarcane mosaic virus and sugarcane yellow leaf virus in sugarcane

USDA-ARS?s Scientific Manuscript database

The importation of sugarcane germplasm is essential to diversify sugarcane germplasm used in United States breeding programs. Foreign germplasm is received primarily as vegetative cuttings. Current permit requirements for importing sugarcane seed into the United States are impractical and limit the ...

Identifying a new causal agent of mosaic in Louisiana sugarcane

USDA-ARS?s Scientific Manuscript database

Sugarcane mosaic virus (SCMV) is a pathogen of economic concern that infects maize, sorghum, and sugarcane worldwide. It is a member of the genus Potyvirus in the family Potyviridae and contains a linear, positive sense ssRNA genome 10 kb long. It is transmitted non-persistently via aphids and ...

Elimination of five sugarcane viruses from sugarcane using in vitro culture of axillary bud and apical meristem

USDA-ARS?s Scientific Manuscript database

Procedures were developed for the in vitro elimination of Sugarcane mosaic virus (SCMV), Sorghum mosaic virus (SrMV), Sugarcane streak mosaic virus (SCSMV), Sugarcane yellow leaf virus (SCYLV) and Fiji disease virus (FDV) from infected sugarcane. In vitro shoot regeneration, elongation and virus el...

Transmission of Turnip yellows virus by Myzus persicae Is Reduced by Feeding Aphids on Double-Stranded RNA Targeting the Ephrin Receptor Protein

PubMed Central

Mulot, Michaël; Monsion, Baptiste; Boissinot, Sylvaine; Rastegar, Maryam; Meyer, Sophie; Bochet, Nicole; Brault, Véronique

2018-01-01

Aphid-transmitted plant viruses are a threat for major crops causing massive economic loss worldwide. Members in the Luteoviridae family are transmitted by aphids in a circulative and non-replicative mode. Virions are acquired by aphids when ingesting sap from infected plants and are transported through the gut and the accessory salivary gland (ASG) cells by a transcytosis mechanism relying on virus-specific receptors largely unknown. Once released into the salivary canal, virions are inoculated to plants, together with saliva, during a subsequent feeding. In this paper, we bring in vivo evidence that the membrane-bound Ephrin receptor (Eph) is a novel aphid protein involved in the transmission of the Turnip yellows virus (TuYV, Polerovirus genus, Luteoviridae family) by Myzus persicae. The minor capsid protein of TuYV, essential for aphid transmission, was able to bind the external domain of Eph in yeast. Feeding M. persicae on in planta- or in vitro-synthesized dsRNA targeting Eph-mRNA (dsRNAEph) did not affect aphid feeding behavior but reduced accumulation of TuYV genomes in the aphid's body. Consequently, TuYV transmission efficiency by the dsRNAEph-treated aphids was reproducibly inhibited and we brought evidence that Eph is likely involved in intestinal uptake of the virion. The inhibition of virus uptake after dsRNAEph acquisition was also observed for two other poleroviruses transmitted by M. persicae, suggesting a broader role of Eph in polerovirus transmission. Finally, dsRNAEph acquisition by aphids did not affect nymph production. These results pave the way toward an ecologically safe alternative of insecticide treatments that are used to lower aphid populations and reduce polerovirus damages. PMID:29593696

Transmission of Turnip yellows virus by Myzus persicae Is Reduced by Feeding Aphids on Double-Stranded RNA Targeting the Ephrin Receptor Protein.

PubMed

Mulot, Michaël; Monsion, Baptiste; Boissinot, Sylvaine; Rastegar, Maryam; Meyer, Sophie; Bochet, Nicole; Brault, Véronique

2018-01-01

Aphid-transmitted plant viruses are a threat for major crops causing massive economic loss worldwide. Members in the Luteoviridae family are transmitted by aphids in a circulative and non-replicative mode. Virions are acquired by aphids when ingesting sap from infected plants and are transported through the gut and the accessory salivary gland (ASG) cells by a transcytosis mechanism relying on virus-specific receptors largely unknown. Once released into the salivary canal, virions are inoculated to plants, together with saliva, during a subsequent feeding. In this paper, we bring in vivo evidence that the membrane-bound Ephrin receptor (Eph) is a novel aphid protein involved in the transmission of the Turnip yellows virus (TuYV, Polerovirus genus, Luteoviridae family) by Myzus persicae . The minor capsid protein of TuYV, essential for aphid transmission, was able to bind the external domain of Eph in yeast. Feeding M. persicae on in planta - or in vitro -synthesized dsRNA targeting Eph -mRNA (dsRNA Eph ) did not affect aphid feeding behavior but reduced accumulation of TuYV genomes in the aphid's body. Consequently, TuYV transmission efficiency by the dsRNA Eph -treated aphids was reproducibly inhibited and we brought evidence that Eph is likely involved in intestinal uptake of the virion. The inhibition of virus uptake after dsRNA Eph acquisition was also observed for two other poleroviruses transmitted by M. persicae , suggesting a broader role of Eph in polerovirus transmission. Finally, dsRNA Eph acquisition by aphids did not affect nymph production. These results pave the way toward an ecologically safe alternative of insecticide treatments that are used to lower aphid populations and reduce polerovirus damages.

Free amino acids - determinant of sugarcane resistance/susceptibility to stalk borer and sap feeders

USDA-ARS?s Scientific Manuscript database

Two relatively new key species in Louisiana that conform to the plant stress hypothesis are the Mexican rice borer, Eoreuma loftini (Dyar) and the sugarcane aphid, Melanaphis sacchari (Zehntner). High performance liquid chromatography differentiated insect resistant and susceptible sugarcane cultiva...

Seasonal Abundance of Aphids and Aphidophagous Insects in Pecan

PubMed Central

Dutcher, James D.; Karar, Haider; Abbas, Ghulam

2012-01-01

Seasonal occurrence of aphids and aphidophagous insects was monitored for six years (2006–2011) from full leaf expansion in May to leaf fall in October in “Desirable” variety pecan trees that were not treated with insecticides. Aphid outbreaks occurred two times per season, once in the spring and again in the late summer. Yellow pecan and blackmargined aphids exceeded the recommended treatment thresholds one time and black pecan aphids exceeded the recommended treatment levels three times over the six seasons. Increases in aphidophagous insect abundance coincided with aphid outbreaks in five of the six seasons. Among aphidophagous insects Harmonia axyridis and Olla v-nigrum were frequently collected in both the tree canopy and at the ground level, whereas, Coccinella septempunctata, Hippodamia convergens were rarely found in the tree canopy and commonly found at the ground level. Green lacewing abundance was higher in the ground level than in the tree canopy. Brown lacewings were more abundant in the tree canopy than at the ground level. Dolichopodid and syrphid fly abundance, at the ground level increased during peak aphid abundance in the tree canopy. Application of an aqueous solution of fermenting molasses to the pecan foliage during an aphid outbreak significantly increased the abundance of ladybeetles and lacewings and significantly reduced the abundance of yellow pecan, blackmargined and black pecan aphids. PMID:26466738

Genetics coupled to quantitative intact proteomics links heritable aphid and endosymbiont protein isoform expression to polerovirus transmission

USDA-ARS?s Scientific Manuscript database

Yellow dwarf viruses in the family Luteoviridae, such as Cereal yellow dwarf virus-RPV (CYDV-RPV), are vectored by aphids and cause the most economically important virus disease of cereal crops worldwide. The identification of aphid proteins mediating virus transmission will better define transmiss...

A report on the transmissibility of Sugarcane mosaic virus and Sugarcane yellow leaf virus through seed in sugarcane

USDA-ARS?s Scientific Manuscript database

In the United States, exotic germplasm of sugarcane (Saccharum spp.) is mainly received as vegetative cuttings because the extensive actions required to meet existing APHIS (Animal and Plant Health Inspection Service) permit conditions make the importation of sugarcane seed impractical. While taking...

Controlling sugarcane diseases in Florida: a challenge in constant evolution

USDA-ARS?s Scientific Manuscript database

Diseases are limiting factors for the sugarcane crop in almost any sugarcane growing location. More than 40 diseases have been recorded in Florida, with brown rust, orange rust and yellow leaf currently impacting on sugarcane production. Ideally, these diseases should be controlled using resistant c...

Controlling sugarcane diseases in Florida: a challenge in constant evolution

USDA-ARS?s Scientific Manuscript database

Diseases are limiting factors for the sugarcane crop in almost any sugarcane growing location. More than 40 diseases have been recorded in Florida, with bown rust, orange rust and yellow leaf currently impacting on sugarcane production. Ideally, these diseases should be controlled using resistant ...

Controlling sugarcane diseases in Florida: a challenge in constant evolution

USDA-ARS?s Scientific Manuscript database

Diseases are limiting factors for the sugarcane crop in almost any sugarcane growing location. More than 40 diseases have been recorded in Florida, with brown rust, orange rust and yellow leaf currently impacting on sugarcane production. Ideally, these diseases should be controlled using resistant...

Contribution of Noncolonizing Aphids to Potato Virus Y Prevalence in Potato in Idaho.

PubMed

Mondal, Shaonpius; Wenninger, Erik J; Hutchinson, Pamela J S; Weibe, Monica A; Eigenbrode, Sanford D; Bosque-Pérez, Nilsa A

2016-12-01

Potato virus Y (PVY) is a major concern for potato production in the United States given its impact on both crop quality and yield. Although green peach aphid, Myzus persicae (Sulzer), is the most efficient PVY vector, it may be less abundant in potato-growing areas of Idaho relative to non-potato-colonizing aphid vectors of PVY that may disperse from nearby cereal fields and other crops. A field study was conducted during 2012-2013 to examine if noncolonizing aphids disperse to nearby potato fields as cereal crops dry down before harvest. The aphid fauna was sampled weekly in four different potato fields in south-central and southeastern Idaho using yellow sticky traps and yellow pan traps. Potato fields were chosen with an adjacent cereal field such that the prevailing westerly wind would facilitate aphid dispersal from cereal fields to potato. Non-potato-colonizing aphids sampled included 10 cereal aphid species, the most abundant of which were Rhopalosiphum padi L. and Metopolophium dirhodum (Walker). More than 35 species from noncereal hosts also were found. Overall, green peach aphid abundance was relatively low, ranging from 0.5-2.5% of the total aphid capture between years and among fields. In both years and all locations, cereal aphid abundance peaked in mid- to late July (cereal ripening stage) and decreased thereafter as cereal crops dried. PVY prevalence in the potato fields increased following these increases in aphid abundance. This study suggests that cereal aphids and other noncolonizing aphids are important contributors to PVY prevalence in potato in southern Idaho. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Analysis of an RNA-seq Strand-Specific Library from an East Timorese Cucumber Sample Reveals a Complete Cucurbit aphid-borne yellows virus Genome.

PubMed

Maina, Solomon; Edwards, Owain R; de Almeida, Luis; Ximenes, Abel; Jones, Roger A C

2017-05-11

Analysis of an RNA-seq library from cucumber leaf RNA extracted from a fast technology for analysis of nucleic acids (FTA) card revealed the first complete genome of Cucurbit aphid-borne yellows virus (CABYV) from East Timor. We compare it with 35 complete CABYV genomes from other world regions. It most resembled the genome of the South Korean isolate HD118. Copyright © 2017 Maina et al.

Analysis of an RNA-seq Strand-Specific Library from an East Timorese Cucumber Sample Reveals a Complete Cucurbit aphid-borne yellows virus Genome

PubMed Central

Maina, Solomon; Edwards, Owain R.; de Almeida, Luis; Ximenes, Abel

2017-01-01

ABSTRACT Analysis of an RNA-seq library from cucumber leaf RNA extracted from a fast technology for analysis of nucleic acids (FTA) card revealed the first complete genome of Cucurbit aphid-borne yellows virus (CABYV) from East Timor. We compare it with 35 complete CABYV genomes from other world regions. It most resembled the genome of the South Korean isolate HD118. PMID:28495776

Genetics coupled to quantitative intact proteomics links heritable aphid and endosymbiont protein expression to circulative polerovirus transmission.

PubMed

Cilia, M; Tamborindeguy, C; Fish, T; Howe, K; Thannhauser, T W; Gray, S

2011-03-01

Yellow dwarf viruses in the family Luteoviridae, which are the causal agents of yellow dwarf disease in cereal crops, are each transmitted most efficiently by different species of aphids in a circulative manner that requires the virus to interact with a multitude of aphid proteins. Aphid proteins differentially expressed in F2 Schizaphis graminum genotypes segregating for the ability to transmit Cereal yellow dwarf virus-RPV (CYDV-RPV) were identified using two-dimensional difference gel electrophoresis (DIGE) coupled to either matrix-assisted laser desorption ionization-tandem mass spectrometry or online nanoscale liquid chromatography coupled to electrospray tandem mass spectrometry. A total of 50 protein spots, containing aphid proteins and proteins from the aphid's obligate and maternally inherited bacterial endosymbiont, Buchnera, were identified as differentially expressed between transmission-competent and refractive aphids. Surprisingly, in virus transmission-competent F2 genotypes, the isoelectric points of the Buchnera proteins did not match those in the maternal Buchnera proteome as expected, but instead they aligned with the Buchnera proteome of the transmission-competent paternal parent. Among the aphid proteins identified, many were involved in energy metabolism, membrane trafficking, lipid signaling, and the cytoskeleton. At least eight aphid proteins were expressed as heritable, isoelectric point isoform pairs, one derived from each parental lineage. In the F2 genotypes, the expression of aphid protein isoforms derived from the competent parental lineage aligned with the virus transmission phenotype with high precision. Thus, these isoforms are candidate biomarkers for CYDV-RPV transmission in S. graminum. Our combined genetic and DIGE approach also made it possible to predict where several of the proteins may be expressed in refractive aphids with different barriers to transmission. Twelve proteins were predicted to act in the hindgut of the aphid

Genome characterization of sugarcane yellow leaf virus from China reveals a novel recombinant genotype.

PubMed

Lin, Yi-Hua; Gao, San-Ji; Damaj, Mona B; Fu, Hua-Ying; Chen, Ru-Kai; Mirkov, T Erik

2014-06-01

Sugarcane yellow leaf virus (SCYLV; genus Polerovirus, family Luteoviridae) is a recombinant virus associated with yellow leaf disease, a serious threat to sugarcane in China and worldwide. Among the nine known SCYLV genotypes existing worldwide, COL, HAW, REU, IND, CHN1, CHN2, BRA, CUB and PER, the last five have been reported in China. In this study, the complete genome sequences (5,880 nt) of GZ-GZ18 and HN-CP502 isolates from the Chinese provinces of Guizhou and Hainan, respectively, were cloned, sequenced and characterized. Phylogenetic analysis showed that, among 29 SCYLV isolates described worldwide, the two Chinese isolates clustered together into an independent clade based on the near-complete genome nucleotide (ORF0-ORF5) or amino acid sequences of individual genes, except for the MP protein (ORF4). We propose that the two isolates represent a novel genotype, CHN3, diverging from other genotypes by 1.7-13.6 % nucleotide differences in ORF0-ORF5, and 2.7-28.1 %, 1.8-20.4 %, 0.5-5.1 % and 2.7-15.9 % amino acid differences in P0 (ORF0), RdRp (RNA-dependent RNA polymerase) (ORF1+2), CP (coat protein) (ORF3) and RT (readthrough protein) (ORF3+5), respectively. CHN3 was closely related to the BRA, HAW and PER genotypes, differing by 1.7-3.8 % in the near-complete genome nucleotide sequence. Recombination analysis further identified CHN3 as a new recombinant strain, arising from the major parent CHN-HN1 and the minor parent CHN-GD-WY19. Recombination breakpoints were distributed mostly within the RdRp region in CHN3 and the four significant recombinant genotypes, IND, REU, CUB and BRA. Recombination is considered to contribute significantly to the evolution and emergence of such new SCYLV variants.

Viral metagenomic-based screening of sugarcane from Florida reveals occurrence of six sugarcane-infecting viruses and high prevalence of Sugarcane yellow leaf virus

USDA-ARS?s Scientific Manuscript database

A viral metagenomics study of the sugarcane virome in Florida was performed in 2013/2014 to analyze the occurrence of known and potentially new viruses. Two hundred and fourteen sugarcane leaf samples were collected from commercial sugarcane (Saccharum interspecific hybrids) fields in Florida and fr...

The Polerovirus Minor Capsid Protein Determines Vector Specificity and Intestinal Tropism in the Aphid

PubMed Central

Brault, Véronique; Périgon, Sophie; Reinbold, Catherine; Erdinger, Monique; Scheidecker, Danièle; Herrbach, Etienne; Richards, Ken; Ziegler-Graff, Véronique

2005-01-01

Aphid transmission of poleroviruses is highly specific, but the viral determinants governing this specificity are unknown. We used a gene exchange strategy between two poleroviruses with different vectors, Beet western yellows virus (BWYV) and Cucurbit aphid-borne yellows virus (CABYV), to analyze the role of the major and minor capsid proteins in vector specificity. Virus recombinants obtained by exchanging the sequence of the readthrough domain (RTD) between the two viruses replicated in plant protoplasts and in whole plants. The hybrid readthrough protein of chimeric viruses was incorporated into virions. Aphid transmission experiments using infected plants or purified virions revealed that vector specificity is driven by the nature of the RTD. BWYV and CABYV have specific intestinal sites in the vectors for endocytosis: the midgut for BWYV and both midgut and hindgut for CABYV. Localization of hybrid virions in aphids by transmission electron microscopy revealed that gut tropism is also determined by the viral origin of the RTD. PMID:16014930

Barley yellow dwarf virus: Luteoviridae or Tombusviridae?

PubMed

Miller, W Allen; Liu, Sijun; Beckett, Randy

2002-07-01

Summary Barley yellow dwarf virus (BYDV), the most economically important virus of small grains, features highly specialised relationships with its aphid vectors, a plethora of novel translation mechanisms mediated by long-distance RNA interactions, and an ambiguous taxonomic status. The structural and movement proteins of BYDV that confer aphid transmission and phloem-limitation properties resemble those of the Luteoviridae, the family in which BYDV is classified. In contrast, many genes and cis-acting signals involved in replication and gene expression most closely resemble those of the Tombusviridae. BYDV is in genus Luteovirus, family Luteoviridae. BYDV includes at least two serotypes or viruses: BYDV-PAV and BYDV-MAV. The former BYDV-RPV is now Cereal yellow dwarf virus-RPV (CYDV-RPV). CYDV is in genus Polerovirus, family Luteoviridae. Genus Luteovirus shares many features with family Tombusviridae. Physical properties: approximately 25 nm icosahedral (T = 3) virions. One major (22 kDa) and one minor (50-55 kDa) coat protein. 5.6-5.8 kb positive sense RNA genome with no 5'-cap and no poly(A) tail. Most grasses. Most important in oats, barley and wheat. Also infects maize and rice. Yellowing and dwarfing in barley, stunting in wheat; reddening, yellowing and blasting in oats. Some isolates cause leaf notching and curling. Key attractions: Model for the study of circulative transmission of aphid-transmitted viruses. Plethora of unusual translation mechanisms. Evidence of recombination in recent evolutionary history creates taxonomic ambiguity. Economically important virus of wheat, barley and oats, worldwide. Useful websites/meetings: International symposium: 'Barley Yellow Dwarf Disease: Recent Advances and Future Strategies', CIMMYT, El Batan, Mexico, 1-5 September 2002, http://www.cimmyt.cgiar.org/Research/wheat/Conf_BYD_02/invitation.htm http://www.cimmyt.org/Research/wheat/BYDVNEWS/htm/BYDVNEWS.htm Aphid transmission animation: http://www.ppws.vt.edu/~sforza/tmv/bydv_aph.html.

Genetics Coupled to Quantitative Intact Proteomics Links Heritable Aphid and Endosymbiont Protein Expression to Circulative Polerovirus Transmission▿ †

PubMed Central

Cilia, M.; Tamborindeguy, C.; Fish, T.; Howe, K.; Thannhauser, T. W.; Gray, S.

2011-01-01

Yellow dwarf viruses in the family Luteoviridae, which are the causal agents of yellow dwarf disease in cereal crops, are each transmitted most efficiently by different species of aphids in a circulative manner that requires the virus to interact with a multitude of aphid proteins. Aphid proteins differentially expressed in F2 Schizaphis graminum genotypes segregating for the ability to transmit Cereal yellow dwarf virus-RPV (CYDV-RPV) were identified using two-dimensional difference gel electrophoresis (DIGE) coupled to either matrix-assisted laser desorption ionization-tandem mass spectrometry or online nanoscale liquid chromatography coupled to electrospray tandem mass spectrometry. A total of 50 protein spots, containing aphid proteins and proteins from the aphid's obligate and maternally inherited bacterial endosymbiont, Buchnera, were identified as differentially expressed between transmission-competent and refractive aphids. Surprisingly, in virus transmission-competent F2 genotypes, the isoelectric points of the Buchnera proteins did not match those in the maternal Buchnera proteome as expected, but instead they aligned with the Buchnera proteome of the transmission-competent paternal parent. Among the aphid proteins identified, many were involved in energy metabolism, membrane trafficking, lipid signaling, and the cytoskeleton. At least eight aphid proteins were expressed as heritable, isoelectric point isoform pairs, one derived from each parental lineage. In the F2 genotypes, the expression of aphid protein isoforms derived from the competent parental lineage aligned with the virus transmission phenotype with high precision. Thus, these isoforms are candidate biomarkers for CYDV-RPV transmission in S. graminum. Our combined genetic and DIGE approach also made it possible to predict where several of the proteins may be expressed in refractive aphids with different barriers to transmission. Twelve proteins were predicted to act in the hindgut of the aphid

Genetic diversity and potential vectors and reservoirs of Cucurbit aphid-borne yellows virus in southeastern Spain.

PubMed

Kassem, Mona A; Juarez, Miguel; Gómez, Pedro; Mengual, Carmen M; Sempere, Raquel N; Plaza, María; Elena, Santiago F; Moreno, Aranzazu; Fereres, Alberto; Aranda, Miguel A

2013-11-01

The genetic variability of a Cucurbit aphid-borne yellows virus (CABYV) (genus Polerovirus, family Luteoviridae) population was evaluated by determining the nucleotide sequences of two genomic regions of CABYV isolates collected in open-field melon and squash crops during three consecutive years in Murcia (southeastern Spain). A phylogenetic analysis showed the existence of two major clades. The sequences did not cluster according to host, year, or locality of collection, and nucleotide similarities among isolates were 97 to 100 and 94 to 97% within and between clades, respectively. The ratio of nonsynonymous to synonymous nucleotide substitutions reflected that all open reading frames have been under purifying selection. Estimates of the population's genetic diversity were of the same magnitude as those previously reported for other plant virus populations sampled at larger spatial and temporal scales, suggesting either the presence of CABYV in the surveyed area long before it was first described, multiple introductions, or a particularly rapid diversification. We also determined the full-length sequences of three isolates, identifying the occurrence and location of recombination events along the CABYV genome. Furthermore, our field surveys indicated that Aphis gossypii was the major vector species of CABYV and the most abundant aphid species colonizing melon fields in the Murcia (Spain) region. Our surveys also suggested the importance of the weed species Ecballium elaterium as an alternative host and potential virus reservoir.

Discovery and targeted LC-MS/MS of purified polerovirus reveals differences in the virus-host interactome associated with altered aphid transmission

USDA-ARS?s Scientific Manuscript database

The transmission of viruses in the Luteoviridae, such as Cereal yellow dwarf virus (CYDV), requires a series of precisely orchestrated interactions between virus proteins, plant proteins, and aphid proteins. These viruses are retained in the phloem for aphid acquisition and are transmitted by aphids...

Ring structure amino acids affect the suppressor activity of melon aphid-borne yellows virus P0 protein.

PubMed

Han, Yan-Hong; Xiang, Hai-Ying; Wang, Qian; Li, Yuan-Yuan; Wu, Wen-Qi; Han, Cheng-Gui; Li, Da-Wei; Yu, Jia-Lin

2010-10-10

Melon aphid-borne yellows virus (MABYV) is a newly identified polerovirus occurring in China. Here, we demonstrate that the MABYV encoded P0 (P0(MA)) protein is a strong suppressor of post-transcriptional gene silencing (PTGS) with activity comparable to tobacco etch virus (TEV) HC-Pro. In addition we have shown that the LP F-box motif present at the N-terminus of P0(MA) is required for suppressor activity. Detailed mutational analyses on P0(MA) revealed that changing the conserved Trp 212 with non-ring structured amino acids altered silencing suppressor functions. Ala substitutions at positions 12 and 211 for Phe had no effect on P0 suppression-activity, whereas Arg and Glu substitutions had greatly decreased suppressor activity. Furthermore, substitutions targeting Phe at position 30 also resulted in reduced P0 suppression-activity. Altogether, these results suggest that ring structured Trp/Phe residues in P0 have important roles in suppressor activity. Copyright © 2010 Elsevier Inc. All rights reserved.

Spatial and Temporal Dynamics of Aphids (Hemiptera: Aphididae) in the Columbia Basin and Northeastern Oregon.

PubMed

Klein, Mathew L; Rondon, Silvia I; Walenta, Darrin L; Zeb, Qamar; Murphy, Alexzandra F

2017-08-01

Aphid species, such as the potato aphid, Macrosiphum euphorbiae Thomas, and the green peach aphid, Myzus persicae Sulzer, are routinely considered the most important pests of potatoes. Potato aphid, green peach aphid, and more recently, other aphids such as the bird cherry-oat aphid Rhopalosiphum padi L. have been identified as vectors of multiple plant pathogenic viruses in potatoes. Since 2006, an area-wide trapping network consisting of ∼60 sites was developed through collaboration between researchers, extension faculty, and stakeholders, to monitor aphid populations in the Columbia Basin of Oregon (Umatilla and Morrow counties) and in northeastern Oregon (Union and Baker counties). Over a 9-yr period (2006 to 2014), aphid specimens were collected weekly using yellow bucket traps and specimens were then identified and counted to determine population levels during the growing season (May-September). Thus, aphid population data were compiled and subjected to spatial and temporal distribution analysis. Weather data, obtained from an established network of weather stations located in the monitoring areas, were used in a nonparametric multiplicative regression analysis to determine which abiotic variables may impact aphid populations. Weather conditions were characterized using confidence intervals (CIs) established based on weather data from 1999 to 2005 for each environmental variable. Aphid populations were found to have a heterogeneous distribution in most years; a few sites had high aphid populations while low numbers were observed at most sites; aphids were also found to correlate with several abiotic variables, namely, elevation, previous season temperature, and previous season dew point. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Estimation of the number of aphids carrying Citrus tristeza virus that visit adult citrus trees.

PubMed

Marroquín, Carlos; Olmos, Antonio; Teresa Gorris, María; Bertolini, Edson; Carmen Martínez, M; Carbonell, Emilio A; Hermoso de Mendoza, Alfonso; Cambra, Mariano

2004-03-01

Aphid species were counted on citrus trees in orchards in Valencia, Spain, in the spring and autumn of 1997, 1998 and 1999. Moericke yellow water traps, the 'sticky shoot' method and counts of established colonies were used in extensive surveys in which 29,502 aphids were recorded and identified. Aphis spiraecola and Aphis gossypii were the most abundant aphid species. The numbers of aphid species landing on mature trees of grapefruit, sweet orange, lemon and clementine and satsuma mandarins, were estimated by counting the numbers of young shoots/tree and aphids trapped on sticky shoots. The proportions of the different aphid species captured were: A. gossypii (53%), A. spiraecola (32%), Toxoptera aurantii (11%), Myzus persicae (1%), Aphis craccivora (1%) and other species (2%). Clementine was the most visited species with 266,700 aphids landing/tree in spring 2000, followed by lemon (147,000), sweet orange (129,150), grapefruit (103,200), and satsuma (92,400). The numbers and relative percentages of aphids carrying Citrus tristeza virus (CTV) were assessed by nested RT-PCR in single closed tubes and analysed by extraction of RNA-CTV targets from trapped aphids. An average of 37,190 CTV-carrying aphids visited each tree in spring 2000 (29 per shoot). The percentage detection of viral RNA in the aphid species that landed were 27% for A. gossypii, 23% for A. spiraecola and 19% for T. aurantii. This high incidence of aphids carrying CTV is consistent with the high prevalence and rapid spread of CTV in sweet orange, clementine, and satsuma mandarins in recent years in the region. The infection rate was proportional to the number of aphids landing/tree.

Differential Life History Trait Associations of Aphids with Nonpersistent Viruses in Cucurbits.

PubMed

Angelella, G M; Egel, D S; Holland, J D; Nemacheck, J A; Williams, C E; Kaplan, I

2015-06-01

The diversity of vectors and fleeting nature of virus acquisition and transmission renders nonpersistent viruses a challenge to manage. We assessed the importance of noncolonizing versus colonizing vectors with a 2-yr survey of aphids and nonpersistent viruses on commercial pumpkin farms. We quantified aphid alightment using pan traps, while testing leaf samples with multiplex RT-PCR targeting cucumber mosaic virus (CMV), zucchini yellow mosaic virus (ZYMV), watermelon mosaic virus (WMV), and papaya ringspot virus (PRSV). Overall, we identified 53 aphid species (3,899 individuals), from which the melon aphid, Aphis gossypii Glover, a pumpkin-colonizing species, predominated (76 and 37% of samples in 2010 and 2011, respectively). CMV and ZYMV were not detected, but WMV and PRSV were prevalent, both regionally (WMV: 28/29 fields, PRSV: 21/29 fields) and within fields (infection rates = 69 and 55% for WMV in 2010 and 2011; 28 and 25% for PRSV in 2010 and 2011). However, early-season samples showed extremely low infection levels, suggesting cucurbit viruses are not seed-transmitted and implicating aphid activity as a causal factor driving virus spread. Interestingly, neither noncolonizer and colonizer alightment nor total aphid alightment were good predictors of virus presence, but community analyses revealed species-specific relationships. For example, cowpea aphid (Aphis craccivora Koch) and spotted alfalfa aphid (Therioaphis trifolii Monell f. maculata) were associated with PRSV infection, whereas the oleander aphid (Aphis nerii Bover de Fonscolombe) was associated with WMV spread within fields. These outcomes highlight the need for tailored management plans targeting key vectors of nonpersistent viruses in agricultural systems. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The complete nucleotide sequence of the genome of Barley yellow dwarf virus-RMV reveals it to be a new Polerovirus distantly related to other yellow dwarf viruses

PubMed Central

Krueger, Elizabeth N.; Beckett, Randy J.; Gray, Stewart M.; Miller, W. Allen

2013-01-01

The yellow dwarf viruses (YDVs) of the Luteoviridae family represent the most widespread group of cereal viruses worldwide. They include the Barley yellow dwarf viruses (BYDVs) of genus Luteovirus, the Cereal yellow dwarf viruses (CYDVs) and Wheat yellow dwarf virus (WYDV) of genus Polerovirus. All of these viruses are obligately aphid transmitted and phloem-limited. The first described YDVs (initially all called BYDV) were classified by their most efficient vector. One of these viruses, BYDV-RMV, is transmitted most efficiently by the corn leaf aphid, Rhopalosiphum maidis. Here we report the complete 5612 nucleotide sequence of the genomic RNA of a Montana isolate of BYDV-RMV (isolate RMV MTFE87, Genbank accession no. KC921392). The sequence revealed that BYDV-RMV is a polerovirus, but it is quite distantly related to the CYDVs or WYDV, which are very closely related to each other. Nor is BYDV-RMV closely related to any other particular polerovirus. Depending on the gene that is compared, different poleroviruses (none of them a YDV) share the most sequence similarity to BYDV-RMV. Because of its distant relationship to other YDVs, and because it commonly infects maize via its vector, R. maidis, we propose that BYDV-RMV be renamed Maize yellow dwarf virus-RMV (MYDV-RMV). PMID:23888156

The complete nucleotide sequence of the genome of Barley yellow dwarf virus-RMV reveals it to be a new Polerovirus distantly related to other yellow dwarf viruses.

PubMed

Krueger, Elizabeth N; Beckett, Randy J; Gray, Stewart M; Miller, W Allen

2013-01-01

The yellow dwarf viruses (YDVs) of the Luteoviridae family represent the most widespread group of cereal viruses worldwide. They include the Barley yellow dwarf viruses (BYDVs) of genus Luteovirus, the Cereal yellow dwarf viruses (CYDVs) and Wheat yellow dwarf virus (WYDV) of genus Polerovirus. All of these viruses are obligately aphid transmitted and phloem-limited. The first described YDVs (initially all called BYDV) were classified by their most efficient vector. One of these viruses, BYDV-RMV, is transmitted most efficiently by the corn leaf aphid, Rhopalosiphum maidis. Here we report the complete 5612 nucleotide sequence of the genomic RNA of a Montana isolate of BYDV-RMV (isolate RMV MTFE87, Genbank accession no. KC921392). The sequence revealed that BYDV-RMV is a polerovirus, but it is quite distantly related to the CYDVs or WYDV, which are very closely related to each other. Nor is BYDV-RMV closely related to any other particular polerovirus. Depending on the gene that is compared, different poleroviruses (none of them a YDV) share the most sequence similarity to BYDV-RMV. Because of its distant relationship to other YDVs, and because it commonly infects maize via its vector, R. maidis, we propose that BYDV-RMV be renamed Maize yellow dwarf virus-RMV (MYDV-RMV).

First full-length genome sequence of the polerovirus luffa aphid-borne yellows virus (LABYV) reveals the presence of at least two consensus sequences in an isolate from Thailand.

PubMed

Knierim, Dennis; Maiss, Edgar; Kenyon, Lawrence; Winter, Stephan; Menzel, Wulf

2015-10-01

Luffa aphid-borne yellows virus (LABYV) was proposed as the name for a previously undescribed polerovirus based on partial genome sequences obtained from samples of cucurbit plants collected in Thailand between 2008 and 2013. In this study, we determined the first full-length genome sequence of LABYV. Based on phylogenetic analysis and genome properties, it is clear that this virus represents a distinct species in the genus Polerovirus. Analysis of sequences from sample TH24, which was collected in 2010 from a luffa plant in Thailand, reveals the presence of two different full-length genome consensus sequences.

Efficacy of Chemical Mimicry by Aphid Predators Depends on Aphid-Learning by Ants.

PubMed

Hayashi, Masayuki; Nomura, Masashi; Nakamuta, Kiyoshi

2016-03-01

Chemical mimicry is an effective strategy when signal receivers recognize and discriminate models by relying on chemical cues. Some aphid enemies mimic the cuticular chemicals of aphids through various means thus avoiding detection and attack by aphid-tending ants. However, because ants have been reported to learn the chemical signatures of aphids in order to distinguish the aphids, the efficacy of chemical mimicry is predicted to depend on the experience of the ants that had tended aphids. The present study tested this hypothesis using two predator species: larvae of the green lacewing Mallada desjardinsi, and larvae of the ladybeetle Scymnus posticalis. Lacewing larvae carry the carcasses of aphids on which they have preyed upon their backs, and these function via chemical camouflage to reduce the aggressiveness of aphid-tending ants toward the larvae. Ladybeetle larvae reportedly produce a covering of wax structures, and their chemicals appear to attenuate ant aggression. We examined whether the behavior of the ant Tetramorium tsushimae toward these predators changed depending on their aphid-tending experience. Ants moderated their aggressiveness toward both predators when they had previously tended aphids, indicating that chemical mimicry by both aphid predators is dependent on previous experience of the ants in tending aphids. Chemical mimicry by the predators of ant-tended aphids is therefore considered to exploit learning-dependent aphid recognition systems of ants.

Aphid Alarm Pheromone as a Cue for Ants to Locate Aphid Partners

PubMed Central

Verheggen, François J.; Diez, Lise; Sablon, Ludovic; Fischer, Christophe; Bartram, Stefan; Haubruge, Eric; Detrain, Claire

2012-01-01

The mutualistic relationships that occur between myrmecophilous aphids and ants are based on the rich food supply that honeydew represents for ants and on the protection they provide against aphid natural enemies. While aphid predators and parasitoids actively forage for oviposition sites by using aphid semiochemicals, scouts of aphid-tending ant species would also benefit from locating honeydew resources by orienting toward aphid pheromone sources. The present study aims to provide additional information on the use of Aphis fabae alarm pheromone, i.e. (E)-β-farnesene (EβF), by ant scouts. The perception and behavioral impact of EβF on Lasius niger were investigated using electroantennography and two bio-assays measuring their attraction and orientation towards aphid semiochemicals. Pronounced electrical depolarizations were observed from L. niger scout antennae to stimulations of A. fabae alarm pheromone, while other sesquiterpenes elicited weak or no responses. L. niger scouts were significantly attracted toward EβF in a four-arm olfactometer, as well as in an two-choice bioassay. These laboratory results suggest for the first time that low amounts of aphid alarm pheromone can be used by L. niger scouts as a cue indicating the presence of aphid colonies and could therefore mediate the aphid-ant partnership in the field. PMID:22870255

Tripartite Interactions of Barley Yellow Dwarf Virus, Sitobion avenae and Wheat Varieties

PubMed Central

Liu, Xiao-Feng; Hu, Xiang-Shun; Keller, Mike A.; Zhao, Hui-Yan; Wu, Yun-Feng; Liu, Tong-Xian

2014-01-01

The tripartite interactions in a pathosystem involving wheat (Triticum aestivum L.), the Barley yellow dwarf virus (BYDV), and the BYDV vector aphid Sitobion avenae were studied under field conditions to determine the impact of these interactions on aphid populations, virus pathology and grain yield. Wheat varietal resistance to BYDV and aphids varied among the three wheat varieties studied over two consecutive years. The results demonstrated that (1) aphid peak number (APN) in the aphid + BYDV (viruliferous aphid) treatment was greater and occurred earlier than that in the non-viruliferous aphid treatment. The APN and the area under the curve of population dynamics (AUC) on a S. avenae-resistant variety 98-10-30 was significantly lower than on two aphid-susceptible varieties Tam200(13)G and Xiaoyan6. (2) The production of alatae (PA) was greater on the variety 98-10-30 than on the other varieties, and PA was greater in the aphid + BYDV treatment on 98-10-30 than in the non-viruliferous aphid treatment, but this trend was reversed on Tam200(13)G and Xiaoyan6. (3) The BYDV disease incidence (DIC) on the variety 98-10-30 was greater than that on the other two varieties in 2012, and the disease index (DID) on Tam200(13)G was lower than on the other varieties in the aphid + BYDV and BYDV treatments in 2012, but not in 2011 when aphid vector numbers were generally lower. (4) Yield loss in the aphid + BYDV treatment tended to be greater than that in the aphid or BYDV alone treatments across varieties and years. We suggested that aphid population development and BYDV transmission tend to promote each other under field conditions. The aphids + BYDV treatment caused greater yield reductions than non-viruliferous aphids or virus treatment. Wheat varietal resistance in 98-10-30 affects the aphid dispersal, virus transmission and wheat yield loss though inhibits aphid populations from increasing. PMID:25184214

Alatae production and population increase of aphid vectors on virus-infected host plants.

PubMed

Blua, M J; Perring, T M

1992-10-01

Zucchini yellow mosaic virus (ZYMV) and Aphis gossypii Glover are two components of a recently identified plant-parasite system that provides an excellent opportunity to study interrelations between a virus and a vector that share the same host, but have no direct physiological interaction. In a field experiment we documented numbers of alate and apterous A. gossypii on healthy Cucurbita pepo and on plants inoculated with virus 0, 7, 14, and 21 days before aphid infestation. When plants were inoculated and infested simultaneously, more than twice as many alatae were produced after 20 days of colony growth than on any other treatment. This indicates that properties unique to the early stages of viral infection somehow stimulated wing formation. Because it is spread by the activities of alatae, virus dispersal would be greater as a result of these properties. Developmental rate, total numbers of aphids, and numbers of alatae and apterae decreased as the time between virus inoculation and aphid colonization increased.

AphidBase: A centralized bioinformatic resource for annotation of the pea aphid genome

PubMed Central

Legeai, Fabrice; Shigenobu, Shuji; Gauthier, Jean-Pierre; Colbourne, John; Rispe, Claude; Collin, Olivier; Richards, Stephen; Wilson, Alex C. C.; Tagu, Denis

2015-01-01

AphidBase is a centralized bioinformatic resource that was developed to facilitate community annotation of the pea aphid genome by the International Aphid Genomics Consortium (IAGC). The AphidBase Information System designed to organize and distribute genomic data and annotations for a large international community was constructed using open source software tools from the Generic Model Organism Database (GMOD). The system includes Apollo and GBrowse utilities as well as a wiki, blast search capabilities and a full text search engine. AphidBase strongly supported community cooperation and coordination in the curation of gene models during community annotation of the pea aphid genome. AphidBase can be accessed at http://www.aphidbase.com. PMID:20482635

Systemic Propagation of a Fluorescent Infectious Clone of a Polerovirus Following Inoculation by Agrobacteria and Aphids

PubMed Central

Boissinot, Sylvaine; Pichon, Elodie; Sorin, Céline; Piccini, Céline; Scheidecker, Danièle; Ziegler-Graff, Véronique; Brault, Véronique

2017-01-01

A fluorescent viral clone of the polerovirus Turnip yellows virus (TuYV) was engineered by introducing the Enhanced Green Fluorescent Protein (EGFP) sequence into the non-structural domain sequence of the readthrough protein, a minor capsid protein. The resulting recombinant virus, referred to as TuYV-RTGFP, was infectious in several plant species when delivered by agroinoculation and invaded efficiently non-inoculated leaves. As expected for poleroviruses, which infect only phloem cells, the fluorescence emitted by TuYV-RTGFP was restricted to the vasculature of infected plants. In addition, TuYV-RTGFP was aphid transmissible and enabled the observation of the initial sites of infection in the phloem after aphid probing in epidermal cells. The aphid-transmitted virus moved efficiently to leaves distant from the inoculation sites and importantly retained the EGFP sequence in the viral genome. This work reports on the first engineered member in the Luteoviridae family that can be visualized by fluorescence emission in systemic leaves of different plant species after agroinoculation or aphid transmission. PMID:28661469

Systemic Propagation of a Fluorescent Infectious Clone of a Polerovirus Following Inoculation by Agrobacteria and Aphids.

PubMed

Boissinot, Sylvaine; Pichon, Elodie; Sorin, Céline; Piccini, Céline; Scheidecker, Danièle; Ziegler-Graff, Véronique; Brault, Véronique

2017-06-29

A fluorescent viral clone of the polerovirus Turnip yellows virus (TuYV) was engineered by introducing the Enhanced Green Fluorescent Protein (EGFP) sequence into the non-structural domain sequence of the readthrough protein, a minor capsid protein. The resulting recombinant virus, referred to as TuYV-RT GFP , was infectious in several plant species when delivered by agroinoculation and invaded efficiently non-inoculated leaves. As expected for poleroviruses, which infect only phloem cells, the fluorescence emitted by TuYV-RT GFP was restricted to the vasculature of infected plants. In addition, TuYV-RT GFP was aphid transmissible and enabled the observation of the initial sites of infection in the phloem after aphid probing in epidermal cells. The aphid-transmitted virus moved efficiently to leaves distant from the inoculation sites and importantly retained the EGFP sequence in the viral genome. This work reports on the first engineered member in the Luteoviridae family that can be visualized by fluorescence emission in systemic leaves of different plant species after agroinoculation or aphid transmission.

Arabidopsis thaliana—Aphid Interaction

PubMed Central

Louis, Joe; Singh, Vijay; Shah, Jyoti

2012-01-01

Aphids are important pests of plants that use their stylets to tap into the sieve elements to consume phloem sap. Besides the removal of photosynthates, aphid infestation also alters source-sink patterns. Most aphids also vector viral diseases. In this chapter, we will summarize on recent significant findings in plant-aphid interaction, and how studies involving Arabidopsis thaliana and Myzus persicae (Sülzer), more commonly known as the green peach aphid (GPA), are beginning to provide important insights into the molecular basis of plant defense and susceptibility to aphids. The recent demonstration that expression of dsRNA in Arabidopsis can be used to silence expression of genes in GPA has further expanded the utility of Arabidopsis for evaluating the contribution of the aphid genome-encoded proteins to this interaction. PMID:22666177

Ants defend aphids against lethal disease

PubMed Central

Nielsen, Charlotte; Agrawal, Anurag A.; Hajek, Ann E.

2010-01-01

Social insects defend their own colonies and some species also protect their mutualist partners. In mutualisms with aphids, ants typically feed on honeydew produced by aphids and, in turn guard and shelter aphid colonies from insect natural enemies. Here we report that Formica podzolica ants tending milkweed aphids, Aphis asclepiadis, protect aphid colonies from lethal fungal infections caused by an obligate aphid pathogen, Pandora neoaphidis. In field experiments, bodies of fungal-killed aphids were quickly removed from ant-tended aphid colonies. Ant workers were also able to detect infective conidia on the cuticle of living aphids and responded by either removing or grooming these aphids. Our results extend the long-standing view of ants as mutualists and protectors of aphids by demonstrating focused sanitizing and quarantining behaviour that may lead to reduced disease transmission in aphid colonies. PMID:19923138

Evolutionary history of aphid-plant associations and their role in aphid diversification.

PubMed

Peccoud, Jean; Simon, Jean-Christophe; von Dohlen, Carol; Coeur d'acier, Armelle; Plantegenest, Manuel; Vanlerberghe-Masutti, Flavie; Jousselin, Emmanuelle

2010-01-01

Aphids are intimately linked with their host plants that constitute their only food resource and habitat, and thus impose considerable selective pressure on their evolution. It is therefore commonly assumed that host plants have greatly influenced the diversification of aphids. Here, we review what is known about the role of host plant association on aphid speciation by examining both macroevolutionary and population-level studies. Phylogenetic studies conducted at different taxonomic levels show that, as in many phytophagous insect groups, the radiation of angiosperms has probably favoured the major Tertiary diversification of aphids. These studies also highlight many aphid lineages constrained to sets of related host plants, suggesting strong evolutionary commitment in aphids' host plant choice, but they fail to document cospeciation events between aphid and host lineages. Instead, phylogenies of several aphid genera reveal that divergence events are often accompanied by host shifts, and suggest, without constituting a formal demonstration, that aphid speciation could be a consequence of adaptation to new hosts. Experimental and field studies below the species level support reproductive isolation between host races as partly due to divergent selection by their host plants. Selected traits are mainly feeding performances and life cycle adaptations to plant phenology. Combined with behavioural preference for favourable host species, these divergent adaptations can induce pre- and post-zygotic barriers between host-specialized aphid populations. However, the hypothesis of host-driven speciation is seldom tested formally and must be weighed against overlooked explanations involving geographic isolation and non-ecological reproductive barriers in the process of speciation. Copyright 2010 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Effects of Point Mutations in the Major Capsid Protein of Beet Western Yellows Virus on Capsid Formation, Virus Accumulation, and Aphid Transmission

PubMed Central

Brault, V.; Bergdoll, M.; Mutterer, J.; Prasad, V.; Pfeffer, S.; Erdinger, M.; Richards, K. E.; Ziegler-Graff, V.

2003-01-01

Point mutations were introduced into the major capsid protein (P3) of cloned infectious cDNA of the polerovirus beet western yellows virus (BWYV) by manipulation of cloned infectious cDNA. Seven mutations targeted sites on the S domain predicted to lie on the capsid surface. An eighth mutation eliminated two arginine residues in the R domain, which is thought to extend into the capsid interior. The effects of the mutations on virus capsid formation, virus accumulation in protoplasts and plants, and aphid transmission were tested. All of the mutants replicated in protoplasts. The S-domain mutant W166R failed to protect viral RNA from RNase attack, suggesting that this particular mutation interfered with stable capsid formation. The R-domain mutant R7A/R8A protected ∼90% of the viral RNA strand from RNase, suggesting that lower positive-charge density in the mutant capsid interior interfered with stable packaging of the complete strand into virions. Neither of these mutants systemically infected plants. The six remaining mutants properly packaged viral RNA and could invade Nicotiana clevelandii systemically following agroinfection. Mutant Q121E/N122D was poorly transmitted by aphids, implicating one or both targeted residues in virus-vector interactions. Successful transmission of mutant D172N was accompanied either by reversion to the wild type or by appearance of a second-site mutation, N137D. This finding indicates that D172 is also important for transmission but that the D172N transmission defect can be compensated for by a “reverse” substitution at another site. The results have been used to evaluate possible structural models for the BWYV capsid. PMID:12584348

Volatile communication in plant-aphid interactions.

PubMed

de Vos, Martin; Jander, Georg

2010-08-01

Volatile communication plays an important role in mediating the interactions between plants, aphids, and other organisms in the environment. In response to aphid infestation, many plants initiate indirect defenses through the release of volatiles that attract ladybugs, parasitoid wasps, and other aphid-consuming predators. Aphid-induced volatile release in the model plant Arabidopsis thaliana requires the jasmonate signaling pathway. Volatile release is also induced by infection with aphid-transmitted viruses. Consistent with mathematical models of optimal transmission, viruses that are acquired rapidly by aphids induce volatile release to attract migratory aphids, but discourage long-term aphid feeding. Although the ecology of these interactions is well-studied, further research is needed to identify the molecular basis of aphid-induced and virus-induced changes in plant volatile release. Copyright 2010 Elsevier Ltd. All rights reserved.

Activity of aphids associated with lettuce and broccoli in Spain and their efficiency as vectors of Lettuce mosaic virus.

PubMed

Nebreda, M; Moreno, A; Pérez, N; Palacios, I; Seco-Fernández, V; Fereres, A

2004-03-01

This research sought to identify the aphid virus vector species associated with lettuce and broccoli crops in Spain, and to determine their population dynamics and ability to transmit Lettuce mosaic virus (LMV). Green tile traps and Moericke yellow water-pan traps were used to monitor aphid flights during the spring and autumn growing seasons of 2001. Aphid species feeding on lettuce were counted weekly. The transmission efficiencies of LMV were determined for the aphid species caught most frequently. The Moericke traps generally caught more aphid species than the tile trap, but the latter was the most suitable to estimate flight activity of species involved in virus spread. Spring aphid catches indicated that the main aphid species landing on lettuce in the regions of Madrid and Murcia was Hyperomyzus lactucae, but Brachycaudus helichrysi was also abundant in both regions. In broccoli in the Navarra region, the most abundant species in spring were Aphis fabae, B. helichrysi and H. lactucae. In autumn-sown crops, the main species landing on lettuce in the Madrid region were Hyadaphis coriandri and Aphis spiraecola. In Murcia, A. spiraecola and Myzus persicae were the most abundant, while in Navarra, Therioaphis trifolii, and various Aphis spp. were the most numerous landing on broccoli. The main aphid species colonising lettuce was Nasonovia ribisnigri, but other less abundant colonising species were Aulacorthum solani and Macrosiphum euphorbiae. The most efficient vectors of LMV were M. persicae, Aphis gossypii and M. euphorbiae, while A. fabae and H. lactucae transmitted with low efficiency, and Rhopalosiphum padi and N. ribisnigri did not transmit. Occurrence of LMV epidemics in central Spain in relation to aphid flights and the role of weeds as virus reservoirs is discussed.

Plant immunity in plant–aphid interactions

PubMed Central

Jaouannet, Maëlle; Rodriguez, Patricia A.; Lenoir, Camille J. G.; MacLeod, Ruari; Escudero-Martinez, Carmen; Bos, Jorunn I.B.

2014-01-01

Aphids are economically important pests that cause extensive feeding damage and transmit viruses. While some species have a broad host range and cause damage to a variety of crops, others are restricted to only closely related plant species. While probing and feeding aphids secrete saliva, containing effectors, into their hosts to manipulate host cell processes and promote infestation. Aphid effector discovery studies pointed out parallels between infection and infestation strategies of plant pathogens and aphids. Interestingly, resistance to some aphid species is known to involve plant resistance proteins with a typical NB-LRR domain structure. Whether these resistance proteins indeed recognize aphid effectors to trigger ETI remains to be elucidated. In addition, it was recently shown that unknown aphid derived elicitors can initiate reactive oxygen species (ROS) production and callose deposition and that these responses were dependent on BAK1 (BRASSINOSTERIOD INSENSITIVE 1-ASSOCIATED RECEPTOR KINASE 1) which is a key component of the plant immune system. In addition, BAK-1 contributes to non-host resistance to aphids pointing to another parallel between plant-pathogen and – aphid interactions. Understanding the role of plant immunity and non-host resistance to aphids is essential to generate durable and sustainable aphid control strategies. Although insect behavior plays a role in host selection and non-host resistance, an important observation is that aphids interact with non-host plants by probing the leaf surface, but are unable to feed or establish colonization. Therefore, we hypothesize that aphids interact with non-host plants at the molecular level, but are potentially not successful in suppressing plant defenses and/or releasing nutrients. PMID:25520727

Plant-Aphid Interactions Under Elevated CO2: Some Cues from Aphid Feeding Behavior.

PubMed

Sun, Yucheng; Guo, Huijuan; Ge, Feng

2016-01-01

Although the increasing concentration of atmospheric carbon dioxide (CO2) accelerates the accumulation of carbohydrates and increases the biomass and yield of C3 crop plants, it also reduces their nitrogen concentration. The consequent changes in primary and secondary metabolites affect the palatability of host plants and the feeding of herbivorous insects. Aphids are phloem feeders and are considered the only feeding guild that positively responds to elevated CO2. In this review, we consider how elevated CO2 modifies host defenses, nutrients, and water-use efficiency by altering concentrations of the phytohormones jasmonic acid, salicylic acid, ethylene, and abscisic acid. We will describe how these elevated CO2-induced changes in defenses, nutrients, and water statusfacilitate specific stages of aphid feeding, including penetration, phloem-feeding, and xylem absorption. We conclude that a better understanding of the effects of elevated CO2 on aphids and on aphid damage to crop plants will require research on the molecular aspects of the interaction between plant and aphid but also research on aphid interactions with their intra- and inter-specific competitors and with their natural enemies.

Coupling genetics and proteomics to identify aphid proteins associated with vector-specific transmission of polerovirus (luteoviridae).

PubMed

Yang, Xiaolong; Thannhauser, T W; Burrows, Mary; Cox-Foster, Diana; Gildow, Fred E; Gray, Stewart M

2008-01-01

Cereal yellow dwarf virus-RPV (CYDV-RPV) is transmitted specifically by the aphids Rhopalosiphum padi and Schizaphis graminum in a circulative nonpropagative manner. The high level of vector specificity results from the vector aphids having the functional components of the receptor-mediated endocytotic pathways to allow virus to transverse the gut and salivary tissues. Studies of F(2) progeny from crosses of vector and nonvector genotypes of S. graminum showed that virus transmission efficiency is a heritable trait regulated by multiple genes acting in an additive fashion and that gut- and salivary gland-associated factors are not genetically linked. Utilizing two-dimensional difference gel electrophoresis to compare the proteomes of vector and nonvector parental and F(2) genotypes, four aphid proteins (S4, S8, S29, and S405) were specifically associated with the ability of S. graminum to transmit CYDV-RPV. The four proteins were coimmunoprecipitated with purified RPV, indicating that the aphid proteins are capable of binding to virus. Analysis by mass spectrometry identified S4 as a luciferase and S29 as a cyclophilin, both of which have been implicated in macromolecular transport. Proteins S8 and S405 were not identified from available databases. Study of this unique genetic system coupled with proteomic analysis indicated that these four virus-binding aphid proteins were specifically inherited and conserved in different generations of vector genotypes and suggests that they play a major role in regulating polerovirus transmission.

Discovery and targeted LC-MS/MS of purified polerovirus reveals differences in the virus-host interactome associated with altered aphid transmission.

PubMed

Cilia, Michelle; Peter, Kari A; Bereman, Michael S; Howe, Kevin; Fish, Tara; Smith, Dawn; Gildow, Fredrick; MacCoss, Michael J; Thannhauser, Theodore W; Gray, Stewart M

2012-01-01

Circulative transmission of viruses in the Luteoviridae, such as cereal yellow dwarf virus (CYDV), requires a series of precisely orchestrated interactions between virus, plant, and aphid proteins. Natural selection has favored these viruses to be retained in the phloem to facilitate acquisition and transmission by aphids. We show that treatment of infected oat tissue homogenate with sodium sulfite reduces transmission of the purified virus by aphids. Transmission electron microscopy data indicated no gross change in virion morphology due to treatments. However, treated virions were not acquired by aphids through the hindgut epithelial cells and were not transmitted when injected directly into the hemocoel. Analysis of virus preparations using nanoflow liquid chromatography coupled to tandem mass spectrometry revealed a number of host plant proteins co-purifying with viruses, some of which were lost following sodium sulfite treatment. Using targeted mass spectrometry, we show data suggesting that several of the virus-associated host plant proteins accumulated to higher levels in aphids that were fed on CYDV-infected plants compared to healthy plants. We propose two hypotheses to explain these observations, and these are not mutually exclusive: (a) that sodium sulfite treatment disrupts critical virion-host protein interactions required for aphid transmission, or (b) that host infection with CYDV modulates phloem protein expression in a way that is favorable for virus uptake by aphids. Importantly, the genes coding for the plant proteins associated with virus may be examined as targets in breeding cereal crops for new modes of virus resistance that disrupt phloem-virus or aphid-virus interactions.

Discovery and Targeted LC-MS/MS of Purified Polerovirus Reveals Differences in the Virus-Host Interactome Associated with Altered Aphid Transmission

PubMed Central

Howe, Kevin; Fish, Tara; Smith, Dawn; Gildow, Fredrick; MacCoss, Michael J.; Thannhauser, Theodore W.; Gray, Stewart M.

2012-01-01

Circulative transmission of viruses in the Luteoviridae, such as cereal yellow dwarf virus (CYDV), requires a series of precisely orchestrated interactions between virus, plant, and aphid proteins. Natural selection has favored these viruses to be retained in the phloem to facilitate acquisition and transmission by aphids. We show that treatment of infected oat tissue homogenate with sodium sulfite reduces transmission of the purified virus by aphids. Transmission electron microscopy data indicated no gross change in virion morphology due to treatments. However, treated virions were not acquired by aphids through the hindgut epithelial cells and were not transmitted when injected directly into the hemocoel. Analysis of virus preparations using nanoflow liquid chromatography coupled to tandem mass spectrometry revealed a number of host plant proteins co-purifying with viruses, some of which were lost following sodium sulfite treatment. Using targeted mass spectrometry, we show data suggesting that several of the virus-associated host plant proteins accumulated to higher levels in aphids that were fed on CYDV-infected plants compared to healthy plants. We propose two hypotheses to explain these observations, and these are not mutually exclusive: (a) that sodium sulfite treatment disrupts critical virion-host protein interactions required for aphid transmission, or (b) that host infection with CYDV modulates phloem protein expression in a way that is favorable for virus uptake by aphids. Importantly, the genes coding for the plant proteins associated with virus may be examined as targets in breeding cereal crops for new modes of virus resistance that disrupt phloem-virus or aphid-virus interactions. PMID:23118947

Wide dispersal of aphid-pathogenic Entomophthorales among aphids relies upon migratory alates.

PubMed

Feng, Ming-Guang; Chen, Chun; Chen, Bin

2004-05-01

Entomophthoralean mycoses are of general importance in the natural control of aphids, but mechanisms involved in their dissemination are poorly understood. Despite several possible means of fungal survival, the dispersal of the mycoses in aphids has never been related to the flight of their migratory alates that are able to locate suitable host plants. In this study, aphid-pathogenic fungi proved to be widely disseminated among various aphids by their alates through migratory flight based on the following findings. First, up to 36.6% of the 7139 migratory alates (including nine species of vegetable or cereal aphids) trapped from air > 30 m above the ground in three provinces of China were found bearing eight species of fungal pathogens. Of those, six were aphid-specific Entomophthorales dominated in individual cases by Pandora neoaphidis, which occurs globally but has no resting spores discovered to date. Secondly, infected alates were confirmed to be able to fly for hours, to initiate colonies on plants after flight and to transmit fungal infection to their offspring in a laboratory experiment, in which 238 Sitobion avenae alates were individually flown in a computer-monitoring flight mill system after exposure to a spore shower of P. neoaphidis and then allowed to colonize host plants.

AphID (Lucid key) http://AphID.AphidNet.org

USDA-ARS?s Scientific Manuscript database

This peer-reviewed web site concentrates on the 66 adult alate and apterous aphids that are the world's most cosmopolitan and polyphagous species. The site includes fact sheets about the various aphids species, a glossary of terms helpful to the student, hundreds of photographs and illustrations, a...

Plant–Aphid Interactions Under Elevated CO2: Some Cues from Aphid Feeding Behavior

PubMed Central

Sun, Yucheng; Guo, Huijuan; Ge, Feng

2016-01-01

Although the increasing concentration of atmospheric carbon dioxide (CO2) accelerates the accumulation of carbohydrates and increases the biomass and yield of C3 crop plants, it also reduces their nitrogen concentration. The consequent changes in primary and secondary metabolites affect the palatability of host plants and the feeding of herbivorous insects. Aphids are phloem feeders and are considered the only feeding guild that positively responds to elevated CO2. In this review, we consider how elevated CO2 modifies host defenses, nutrients, and water-use efficiency by altering concentrations of the phytohormones jasmonic acid, salicylic acid, ethylene, and abscisic acid. We will describe how these elevated CO2-induced changes in defenses, nutrients, and water statusfacilitate specific stages of aphid feeding, including penetration, phloem-feeding, and xylem absorption. We conclude that a better understanding of the effects of elevated CO2 on aphids and on aphid damage to crop plants will require research on the molecular aspects of the interaction between plant and aphid but also research on aphid interactions with their intra- and inter-specific competitors and with their natural enemies. PMID:27148325

A peptide that binds the pea aphid gut impedes entry of Pea enation mosaic virus into the aphid hemocoel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Sijun, E-mail: sliu@iastate.ed; Sivakumar, S., E-mail: sivaento@iastate.ed; Sparks, Wendy O., E-mail: wosparks@iastate.ed

2010-05-25

Development of ways to block virus transmission by aphids could lead to novel and broad-spectrum means of controlling plant viruses. Viruses in the Luteoviridae enhanced are obligately transmitted by aphids in a persistent manner that requires virion accumulation in the aphid hemocoel. To enter the hemocoel, the virion must bind and traverse the aphid gut epithelium. By screening a phage display library, we identified a 12-residue gut binding peptide (GBP3.1) that binds to the midgut and hindgut of the pea aphid Acyrthosiphon pisum. Binding was confirmed by labeling the aphid gut with a GBP3.1-green fluorescent protein fusion. GBP3.1 reduced uptakemore » of Pea enation mosaic virus (Luteoviridae) from the pea aphid gut into the hemocoel. GBP3.1 also bound to the gut epithelia of the green peach aphid and the soybean aphid. These results suggest a novel strategy for inhibiting plant virus transmission by at least three major aphid pest species.« less

Population Growth Parameters of Rose Aphid, Macrosiphum rosae (Hemiptera: Aphididae) on Different Rose Cultivars.

PubMed

Golizadeh, A; Jafari-Behi, V; Razmjou, J; Naseri, B; Hassanpour, M

2017-02-01

The rose aphid, Macrosiphum rosae (L.), is one of the most important pests on rose plants (Rosa spp.) with a worldwide distribution. As resistance indices, the development, survivorship, and reproduction of this aphid were evaluated on 10 rose cultivars, including Bella Vita, Cool Water, Dolce Vita, Maroussia, Orange Juice, Pinkpromise, Roulette, Tea, Valentine, and Persian Yellow in laboratory at 25 ± 1°C, 65 ± 5% relative humidity, and photoperiod of 16:8 (L/D) h. Rose aphid successfully survived on all 10 rose cultivars, although mortality rate was higher on Tea and Bella Vita. The number of offspring per female differed significantly among the tested rose cultivars, and ranged from 9.2 on Tea to 38.7 nymphs on Orange Juice. Population growth parameters were significantly affected by rose cultivars. The longest mean generation time (T) was observed on Bella Vita (14.8 days) and Tea (14.7 days) and the shortest on Orange Juice (10.0 days). The net reproductive rate (R 0 ) ranged from 6.9 on Tea to 33.2 nymphs on Orange Juice cultivar. Correspondingly, the highest value of intrinsic rate of increase (r m ) was observed on Orange Juice (0.348 day -1 ) and lower values on Tea (0.131 day -1 ) followed by Bella Vita (0.154 day -1 ). Cluster analysis of all the measured parameters of rose aphid on different rose cultivars revealed that Tea and Bella Vita were relatively resistant to M. rosae. These findings could be useful in developing an integrated pest management (IPM) program for this aphid in urbanized areas and commercial rose potting.

Spatio-temporal distribution and environmental drivers of Barley yellow dwarf virus and vector abundance in Kansas.

PubMed

Enders, Laramy; Hefley, Trevor; Girvin, John; Whitworth, Robert; Smith, Charles

2018-05-11

Several aphid species transmit barley yellow dwarf, a globally destructive disease caused by viruses that infect cereal grain crops. Data from >400 samples collected across Kansas wheat fields in 2014 and 2015 were used to develop spatio-temporal models predicting the extent to which landcover, temperature and precipitation affect spring aphid vector abundance and presence of individuals carrying Barley yellow dwarf virus (BYDV). The distribution of Rhopalosiphum padi abundance was not correlated with climate or landcover, but Sitobion avenae abundance was positively correlated to fall temperature and negatively correlated to spring temperature and precipitation. The abundance of Schizaphis graminum was negatively correlated with fall precipitation and winter temperature. The incidence of viruliferous (+BYDV) R. padi was positively correlated with fall precipitation but negatively correlated with winter precipitation. In contrast, the probability of +BYDV S. avenae was unaffected by precipitation but was positively correlated with average fall temperatures and distance to nearest forest or shrubland. R. padi and S. avenae were more prevalent at Eastern sample sites where ground cover is more grassland than cropland, suggesting that grassland may provide over-summering sites for vectors and pose a risk as potential BYDV reservoirs. Nevertheless, land cover patterns were not strongly associated with differences in abundance or probability that viruliferous aphids were present.

Coupling Genetics and Proteomics To Identify Aphid Proteins Associated with Vector-Specific Transmission of Polerovirus (Luteoviridae)▿

PubMed Central

Yang, Xiaolong; Thannhauser, T. W.; Burrows, Mary; Cox-Foster, Diana; Gildow, Fred E.; Gray, Stewart M.

2008-01-01

Cereal yellow dwarf virus-RPV (CYDV-RPV) is transmitted specifically by the aphids Rhopalosiphum padi and Schizaphis graminum in a circulative nonpropagative manner. The high level of vector specificity results from the vector aphids having the functional components of the receptor-mediated endocytotic pathways to allow virus to transverse the gut and salivary tissues. Studies of F2 progeny from crosses of vector and nonvector genotypes of S. graminum showed that virus transmission efficiency is a heritable trait regulated by multiple genes acting in an additive fashion and that gut- and salivary gland-associated factors are not genetically linked. Utilizing two-dimensional difference gel electrophoresis to compare the proteomes of vector and nonvector parental and F2 genotypes, four aphid proteins (S4, S8, S29, and S405) were specifically associated with the ability of S. graminum to transmit CYDV-RPV. The four proteins were coimmunoprecipitated with purified RPV, indicating that the aphid proteins are capable of binding to virus. Analysis by mass spectrometry identified S4 as a luciferase and S29 as a cyclophilin, both of which have been implicated in macromolecular transport. Proteins S8 and S405 were not identified from available databases. Study of this unique genetic system coupled with proteomic analysis indicated that these four virus-binding aphid proteins were specifically inherited and conserved in different generations of vector genotypes and suggests that they play a major role in regulating polerovirus transmission. PMID:17959668

Epidemiology and integrated management of persistently transmitted aphid-borne viruses of legume and cereal crops in West Asia and North Africa.

PubMed

Makkouk, Khaled M; Kumari, Safaa G

2009-05-01

Cool-season food legumes (faba bean, lentil, chickpea and pea) and cereals (bread and durum wheat and barley) are the most important and widely cultivated crops in West Asia and North Africa (WANA), where they are the main source of carbohydrates and protein for the majority of the population. Persistently transmitted aphid-borne viruses pose a significant limitation to legume and cereal production worldwide. Surveys conducted in many countries in WANA during the last three decades established that the most important of these viruses are: Faba bean necrotic yellows virus (FBNYV: genus Nanovirus; family Nanoviridae), Bean leafroll virus (BLRV: genus Luteovirus; family Luteoviridae), Beet western yellows virus (BWYV: genus Polerovirus; family Luteoviridae), Soybean dwarf virus (SbDV: genus Luteovirus; family Luteoviridae) and Chickpea chlorotic stunt virus (CpCSV: genus Polerovirus; family Luteoviridae) which affect legume crops, and Barley yellow dwarf virus-PAV (BYDV-PAV: genus Luteovirus; family Luteoviridae), Barley yellow dwarf virus-MAV (BYDV-MAV: genus Luteovirus; family Luteoviridae) and Cereal yellow dwarf virus-RPV (CYDV-RPV: genus Polerovirus; family Luteoviridae) which affect cereal crops. Loss in yield caused by these viruses is usually high when infection occurs early in the growing season. Many aphid vector species for the above-mentioned viruses are reported to be prevalent in the WANA region. In addition, in this region many wild species (annual or perennial) were found infected with these viruses and may play an important role in their ecology and spread. Fast spread of these diseases was always associated with high aphid vector populations and activity. Although virus disease management can be achieved by combining several control measures, development of resistant genotypes is undoubtedly one of the most appropriate control methods. Over the last three decades barley and wheat genotypes resistant to BYDV, faba bean genotypes resistant to BLRV, and

The weed Sorghum almum is a putative alternative host of sugarcane infecting viruses in Florida

USDA-ARS?s Scientific Manuscript database

Sorghum almum or Columbus grass is a common weed growing in the Everglades Agricultural Area (EAA). In recent surveys for alternative hosts of sugarcane yellow leaf virus (SCYLV), 123 out of 141 (87%) plants of S. almum tested positive for this virus by tissue blot immunoassay (TBIA) using polyclona...

New poleroviruses associated with yellowing symptoms in different vegetable crops in Greece.

PubMed

Lotos, L; Maliogka, V I; Katis, N I

2016-02-01

Four poleroviral isolates from Greece, two from lettuce, one from spinach and one from watermelon showing yellowing symptoms, were molecularly characterized by analyzing the sequence of a large part of the genome spanning from the 3'-terminal part of the RdRp to the end of the CP gene. The sequences were analyzed for their similarity and phylogenetic relationships to other members of the genus Polerovirus as well as for evidence of recombination events. The results revealed the existence of two putatively new viruses: one from lettuce and one from spinach, provisionally named "lettuce yellows virus" and "spinach yellows virus", respectively. Also, a new recombinant virus infecting lettuce, herein named "lettuce mild yellows virus", and a watermelon isolate of pepo aphid-borne yellows virus (PABYV) were identified. Our study highlights the existence of high genetic diversity within the genus Polerovirus, which could be associated with the emergence of new viral diseases in various crops worldwide.

Escherichia coli K-12 pathogenicity in the pea aphid, Acyrthosiphon pisum, reveals reduced antibacterial defense in aphids.

PubMed

Altincicek, Boran; Ter Braak, Bas; Laughton, Alice M; Udekwu, Klas I; Gerardo, Nicole M

2011-10-01

To better understand the molecular basis underlying aphid immune tolerance to beneficial bacteria and immune defense to pathogenic bacteria, we characterized how the pea aphid Acyrthosiphon pisum responds to Escherichia coli K-12 infections. E. coli bacteria, usually cleared in the hemolymph of other insect species, were capable of growing exponentially and killing aphids within a few days. Red fluorescence protein expressing E. coli K-12 laboratory strain multiplied in the aphid hemolymph as well as in the digestive tract, resulting in death of infected aphids. Selected gene deletion mutants of the E. coli K-12 predicted to have reduced virulence during systemic infections showed no difference in either replication or killing rate when compared to the wild type E. coli strain. Of note, however, the XL1-Blue E. coli K-12 strain exhibited a significant lag phase before multiplying and killing aphids. This bacterial strain has recently been shown to be more sensitive to oxidative stress than other E. coli K-12 strains, revealing a potential role for reactive oxygen species-mediated defenses in the otherwise reduced aphid immune system. Copyright © 2011 Elsevier Ltd. All rights reserved.

Mechanisms and evolution of plant resistance to aphids.

PubMed

Züst, Tobias; Agrawal, Anurag A

2016-01-06

Aphids are important herbivores of both wild and cultivated plants. Plants rely on unique mechanisms of recognition, signalling and defence to cope with the specialized mode of phloem feeding by aphids. Aspects of the molecular mechanisms underlying aphid-plant interactions are beginning to be understood. Recent advances include the identification of aphid salivary proteins involved in host plant manipulation, and plant receptors involved in aphid recognition. However, a complete picture of aphid-plant interactions requires consideration of the ecological outcome of these mechanisms in nature, and the evolutionary processes that shaped them. Here we identify general patterns of resistance, with a special focus on recognition, phytohormonal signalling, secondary metabolites and induction of plant resistance. We discuss how host specialization can enable aphids to co-opt both the phytohormonal responses and defensive compounds of plants for their own benefit at a local scale. In response, systemically induced resistance in plants is common and often involves targeted responses to specific aphid species or even genotypes. As co-evolutionary adaptation between plants and aphids is ongoing, the stealthy nature of aphid feeding makes both the mechanisms and outcomes of these interactions highly distinct from those of other herbivore-plant interactions.

Aphid egg protection by ants: a novel aspect of the mutualism between the tree-feeding aphid Stomaphis hirukawai and its attendant ant Lasius productus

NASA Astrophysics Data System (ADS)

Matsuura, Kenji; Yashiro, Toshihisa

2006-10-01

Aphids often form mutualistic associations with ants, in which the aphids provide the ants with honeydew and the ants defend the aphids from predators. In this paper, we report aphid egg protection by ants as a novel aspect of the deeply interdependent relationship between a tree-feeding aphid and its attendant ant. The ant Lasius productus harbours oviparous females, males, and eggs of the hinoki cypress-feeding aphid Stomaphis hirukawai in its nests in winter. We investigated the behaviour of ants kept with aphid eggs in petri dishes to examine whether the ants recognise the aphid eggs and tend them or only provide a refuge for the aphids. Workers carried almost all of the aphid eggs into the nest within 24 h. The ants indiscriminately tended aphid eggs collected from their own colonies and those from other ant colonies. The ants cleaned the eggs and piled them up in the nest, and egg tending by ants dramatically increased aphid egg survival rates. Starving the ants showed no significant effect on aphid egg survivorship. Without ants, aphid eggs were rapidly killed by fungi. These results suggested that grooming by the ants protected the aphid eggs, at least, against pathogenic fungi. This hygienic service afforded by the ants seems indispensable for egg survival of these aphids in an environment rich in potentially pathogenic microorganisms.

Aphid egg protection by ants: a novel aspect of the mutualism between the tree-feeding aphid Stomaphis hirukawai and its attendant ant Lasius productus.

PubMed

Matsuura, Kenji; Yashiro, Toshihisa

2006-10-01

Aphids often form mutualistic associations with ants, in which the aphids provide the ants with honeydew and the ants defend the aphids from predators. In this paper, we report aphid egg protection by ants as a novel aspect of the deeply interdependent relationship between a tree-feeding aphid and its attendant ant. The ant Lasius productus harbours oviparous females, males, and eggs of the hinoki cypress-feeding aphid Stomaphis hirukawai in its nests in winter. We investigated the behaviour of ants kept with aphid eggs in petri dishes to examine whether the ants recognise the aphid eggs and tend them or only provide a refuge for the aphids. Workers carried almost all of the aphid eggs into the nest within 24 h. The ants indiscriminately tended aphid eggs collected from their own colonies and those from other ant colonies. The ants cleaned the eggs and piled them up in the nest, and egg tending by ants dramatically increased aphid egg survival rates. Starving the ants showed no significant effect on aphid egg survivorship. Without ants, aphid eggs were rapidly killed by fungi. These results suggested that grooming by the ants protected the aphid eggs, at least, against pathogenic fungi. This hygienic service afforded by the ants seems indispensable for egg survival of these aphids in an environment rich in potentially pathogenic microorganisms.

Sequencing and Validation of Reference Genes to Analyze Endogenous Gene Expression and Quantify Yellow Dwarf Viruses Using RT-qPCR in Viruliferous Rhopalosiphum padi

PubMed Central

Wu, Keke; Liu, Wenwen; Mar, Thithi; Liu, Yan; Wu, Yunfeng; Wang, Xifeng

2014-01-01

The bird cherry-oat aphid (Rhopalosiphum padi), an important pest of cereal crops, not only directly sucks sap from plants, but also transmits a number of plant viruses, collectively the yellow dwarf viruses (YDVs). For quantifying changes in gene expression in vector aphids, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) is a touchstone method, but the selection and validation of housekeeping genes (HKGs) as reference genes to normalize the expression level of endogenous genes of the vector and for exogenous genes of the virus in the aphids is critical to obtaining valid results. Such an assessment has not been done, however, for R. padi and YDVs. Here, we tested three algorithms (GeNorm, NormFinder and BestKeeper) to assess the suitability of candidate reference genes (EF-1α, ACT1, GAPDH, 18S rRNA) in 6 combinations of YDV and vector aphid morph. EF-1α and ACT1 together or in combination with GAPDH or with GAPDH and 18S rRNA could confidently be used to normalize virus titre and expression levels of endogenous genes in winged or wingless R. padi infected with Barley yellow dwarf virus isolates (BYDV)-PAV and BYDV-GAV. The use of only one reference gene, whether the most stably expressed (EF-1α) or the least stably expressed (18S rRNA), was not adequate for obtaining valid relative expression data from the RT-qPCR. Because of discrepancies among values for changes in relative expression obtained using 3 regions of the same gene, different regions of an endogenous aphid gene, including each terminus and the middle, should be analyzed at the same time with RT-qPCR. Our results highlight the necessity of choosing the best reference genes to obtain valid experimental data and provide several HKGs for relative quantification of virus titre in YDV-viruliferous aphids. PMID:24810421

Partial aphid resistance in lettuce negatively affects parasitoids.

PubMed

Lanteigne, Marie-Eve; Brodeur, Jacques; Jenni, Sylvie; Boivin, Guy

2014-10-01

This study investigated the effects of partial plant resistance on the lettuce aphid Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae), a major pest of cultivated lettuce (Lactuca sativa L.), and one of its parasitoids, Aphidius ervi Haliday (Hymenoptera: Braconidae). Aphids were reared on susceptible (L. sativa variety Estival; S) or partially resistant (Lactuca serriola L. PI 491093; PR) lettuce, and next parasitized by A. ervi females. Fitness proxies were measured for both aphids and parasitoids. Developmental time to adult stage took longer for alate and apterous aphids (an average of 3.5 and 1.5 additional days, respectively) on PR than on S lettuce, and fecundity of alate aphids reared on PR lettuce was reduced by 37.8% relative to those reared on S lettuce. Size (tibia length) and weight of aphids reared on PR lettuce were lower than for aphids reared on S lettuce from the third and second instar onward, respectively. Parasitism of aphids reared on PR plants resulted in lower parasitoid offspring emergence (-49.9%), lower adult female (-30.3%) and male (-27.5%) weight, smaller adult female (-17.5%) and male (-11.9%) size, and lower female fecundity (37.8% fewer eggs) than when parasitoids developed from aphids reared on S plants. Our results demonstrate that partial aphid resistance in lettuce negatively affects both the second and third trophic levels. Host plant resistance in cultivated lettuce may therefore create an ecological sink for aphid parasitoids.

Chlorotic feeding injury by the black pecan aphid (hemiptera: aphididae) to pecan foliage promotes aphid settling and nymphal development.

PubMed

Cottrell, Ted E; Wood, Bruce W; Ni, Xinzhi

2009-04-01

The nature of the interaction between the black pecan aphid, Melanocallis caryaefoliae (Davis) (Hemiptera: Aphididae), and the chlorosis it causes to foliage of its pecan [Carya illinoinensis (Wangenh.) K. Koch)] host is poorly understood. Laboratory experiments were conducted on the settling behavior of the black pecan aphid, when provided chlorotic pecan leaf discs resulting from previous black pecan aphid feeding and nonchlorotic leaf discs, under a normal photoperiod and constant dark. Additionally, aphid development from the first instar to the adult stage was examined when nymphs were either allowed to feed on the same leaf disc or moved daily to a new, nondamaged, same age leaf disc. After 24 h, a significantly higher percentage of black pecan aphids settled on chlorotic than on nonchlorotic leaf discs, regardless of photoperiod. When starting from the first instar, nymphs that were prevented from inducing leaf chlorosis by moving daily to new, same-age leaf discs took approximately 5 d longer to complete development, had a shorter body length, and had higher mortality than when aphids remained on the same leaf disc. These results show that black pecan aphid-induced leaf chlorosis plays an important role in the interaction of the black pecan aphid with its pecan host.

Isolation of nucleotide binding site-leucine rich repeat and kinase resistance gene analogues from sugarcane (Saccharum spp.).

PubMed

Glynn, Neil C; Comstock, Jack C; Sood, Sushma G; Dang, Phat M; Chaparro, Jose X

2008-01-01

Resistance gene analogues (RGAs) have been isolated from many crops and offer potential in breeding for disease resistance through marker-assisted selection, either as closely linked or as perfect markers. Many R-gene sequences contain kinase domains, and indeed kinase genes have been reported as being proximal to R-genes, making kinase analogues an additionally promising target. The first step towards utilizing RGAs as markers for disease resistance is isolation and characterization of the sequences. Sugarcane clone US01-1158 was identified as resistant to yellow leaf caused by the sugarcane yellow leaf virus (SCYLV) and moderately resistant to rust caused by Puccinia melanocephala Sydow & Sydow. Degenerate primers that had previously proved useful for isolating RGAs and kinase analogues in wheat and soybean were used to amplify DNA from sugarcane (Saccharum spp.) clone US-01-1158. Sequences generated from 1512 positive clones were assembled into 134 contigs of between two and 105 sequences. Comparison of the contig consensuses with the NCBI sequence database using BLASTx showed that 20 had sequence homology to nuclear binding site and leucine rich repeat (NBS-LRR) RGAs, and eight to kinase genes. Alignment of the deduced amino acid sequences with similar sequences from the NCBI database allowed the identification of several conserved domains. The alignment and resulting phenetic tree showed that many of the sequences had greater similarity to sequences from other species than to one another. The use of degenerate primers is a useful method for isolating novel sugarcane RGA and kinase gene analogues. Further studies are needed to evaluate the role of these genes in disease resistance.

Aphid reproductive investment in response to mortality risks

PubMed Central

2010-01-01

Background Aphids are striking in their prodigious reproductive capacity and reliance on microbial endosymbionts, which provision their hosts with necessary amino acids and provide protection against parasites and heat stress. Perhaps as a result of this bacterial dependence, aphids have limited immune function that may leave them vulnerable to bacterial pathogens. An alternative, non-immunological response that may be available to infected aphids is to increase reproduction, thereby ameliorating fitness loss from infection. Such a response would reduce the need to mount a potentially energetically costly immune response, and would parallel that of other hosts that alter life-history traits when there is a risk of infection. Here we examined whether pea aphids (Acyrthosiphon pisum) respond to immunological challenges by increasing reproduction. As a comparison to the response to the internal cue of risk elicited by immunological challenge, we also exposed pea aphids to an external cue of risk - the aphid alarm pheromone (E)-β-farnesene (EBF), which is released in the presence of predators. For each challenge, we also examined whether the presence of symbionts modified the host response, as maintaining host fitness in the face of challenge would benefit both the host and its dependent bacteria. Results We found that aphids stabbed abdominally with a sterile needle had reduced fecundity relative to control aphids but that aphids stabbed with a needle bearing heat-killed bacteria had reproduction intermediate, and statistically indistinguishable, to the aphids stabbed with a sterile needle and the controls. Aphids with different species of facultative symbiotic bacteria had different reproductive patterns overall, but symbionts in general did not alter aphid reproduction in response to bacterial exposure. However, in response to exposure to alarm pheromone, aphids with Hamiltonella defensa or Serratia symbiotica symbiotic infections increased reproduction but those

Facultative symbiont infections affect aphid reproduction.

PubMed

Simon, Jean-Christophe; Boutin, Sébastien; Tsuchida, Tsutomu; Koga, Ryuichi; Le Gallic, Jean-François; Frantz, Adrien; Outreman, Yannick; Fukatsu, Takema

2011-01-01

Some bacterial symbionts alter their hosts reproduction through various mechanisms that enhance their transmission in the host population. In addition to its obligatory symbiont Buchnera aphidicola, the pea aphid Acyrthosiphon pisum harbors several facultative symbionts influencing several aspects of host ecology. Aphids reproduce by cyclical parthenogenesis whereby clonal and sexual reproduction alternate within the annual life cycle. Many species, including the pea aphid, also show variation in their reproductive mode at the population level, with some lineages reproducing by cyclical parthenogenesis and others by permanent parthenogenesis. While the role of facultative symbionts has been well studied during the parthenogenetic phase of their aphid hosts, very little is known on their possible influence during the sexual phase. Here we investigated whether facultative symbionts modulate the capacity to produce sexual forms in various genetic backgrounds of the pea aphid with controlled symbiont composition and also in different aphid genotypes from natural populations with previously characterized infection status and reproductive mode. We found that most facultative symbionts exhibited detrimental effects on their hosts fitness under sex-inducing conditions in comparison with the reference lines. We also showed that the loss of sexual phase in permanently parthenogenetic lineages of A. pisum was not explained by facultative symbionts. Finally, we demonstrated that Spiroplasma infection annihilated the production of males in the host progeny by inducing a male-killing phenotype, an unexpected result for organisms such as aphids that reproduce primarily through clonal reproduction.

Pyramiding different aphid-resistance genes in elite soybean germplasm to combat dynamic aphid populations

USDA-ARS?s Scientific Manuscript database

The soybean aphid, an invasive species, has posed a significant threat to soybean production in North America since 2001. Use of resistant cultivars is an effective tactic to protect soybean yield. However, the variability and dynamics of aphid populations could limit the effectiveness of host-resis...

Agroinfection as an alternative to insects for infecting plants with beet western yellows luteovirus.

PubMed Central

Leiser, R M; Ziegler-Graff, V; Reutenauer, A; Herrbach, E; Lemaire, O; Guilley, H; Richards, K; Jonard, G

1992-01-01

Beet western yellows luteovirus, like other luteoviruses, cannot be transmitted to host plants by mechanical inoculation but requires an aphid vector, a feature that has heretofore presented a serious obstacle to the study of such viruses. In this paper we describe use of agroinfection to infect hosts with beet western yellows virus without recourse to aphids. Agroinfection is a procedure for introducing a plant virus into a host via Agrobacterium tumefaciens harboring a Ti plasmid, which can efficiently transfer a portion of the plasmid (T-DNA) to plant cells near a wound. The viral genome must be inserted into the T-DNA in such a way that it can escape and begin autonomous replication, a requirement that has, so far, limited agroinfection to pathogens with a circular genome. We have cloned cDNA corresponding to the complete beet western yellows virus RNA genome between the cauliflower mosaic virus 35S promoter and the nopaline synthase transcription termination signal. In one construct, a self-cleaving (ribozyme) sequence was included so as to produce a transcript in planta with a 3' extremity almost identical to natural viral RNA. When inoculated mechanically to host plants, the naked plasmid DNA was not infectious but, when introduced into T-DNA and agroinfected to plants, both the construct with and without the ribozyme produced an infection. This approach should be applicable to virtually any plant virus with a linear plus-strand RNA genome. Images PMID:1409615

Armet is an effector protein mediating aphid-plant interactions.

PubMed

Wang, Wei; Dai, Huaien; Zhang, Yi; Chandrasekar, Raman; Luo, Lan; Hiromasa, Yasuaki; Sheng, Changzhong; Peng, Gongxin; Chen, Shaoliang; Tomich, John M; Reese, John; Edwards, Owain; Kang, Le; Reeck, Gerald; Cui, Feng

2015-05-01

Aphid saliva is predicted to contain proteins that modulate plant defenses and facilitate feeding. Armet is a well-characterized bifunctional protein in mammalian systems. Here we report a new role of Armet, namely as an effector protein in the pea aphid, Acyrthosiphon pisum. Pea aphid Armet's physical and chemical properties and its intracellular role are comparable to those reported for mammalian Armets. Uniquely, we detected Armet in aphid watery saliva and in the phloem sap of fava beans fed on by aphids. Armet's transcript level is several times higher in the salivary gland when aphids feed on bean plants than when they feed on an artificial diet. Knockdown of the Armet transcript by RNA interference disturbs aphid feeding behavior on fava beans measured by the electrical penetration graph technique and leads to a shortened life span. Inoculation of pea aphid Armet protein into tobacco leaves induced a transcriptional response that included pathogen-responsive genes. The data suggest that Armet is an effector protein mediating aphid-plant interactions. © FASEB.

Aphid-encoded variability in susceptibility to a parasitoid

PubMed Central

2014-01-01

Background Many animals exhibit variation in resistance to specific natural enemies. Such variation may be encoded in their genomes or derived from infection with protective symbionts. The pea aphid, Acyrthosiphon pisum, for example, exhibits tremendous variation in susceptibility to a common natural enemy, the parasitic wasp Aphidius ervi. Pea aphids are often infected with the heritable bacterial symbiont, Hamiltonella defensa, which confers partial to complete resistance against this parasitoid depending on bacterial strain and associated bacteriophages. That previous studies found that pea aphids without H. defensa (or other symbionts) were generally susceptible to parasitism, together with observations of a limited encapsulation response, suggested that pea aphids largely rely on infection with H. defensa for protection against parasitoids. However, the limited number of uninfected clones previously examined, and our recent report of two symbiont-free resistant clones, led us to explicitly examine aphid-encoded variability in resistance to parasitoids. Results After rigorous screening for known and unknown symbionts, and microsatellite genotyping to confirm clonal identity, we conducted parasitism assays using fifteen clonal pea aphid lines. We recovered significant variability in aphid-encoded resistance, with variation levels comparable to that contributed by H. defensa. Because resistance can be costly, we also measured aphid longevity and cumulative fecundity of the most and least resistant aphid lines under permissive conditions, but found no trade-offs between higher resistance and these fitness parameters. Conclusions These results indicate that pea aphid resistance to A. ervi is more complex than previously appreciated, and that aphids employ multiple tactics to aid in their defense. While we did not detect a tradeoff, these may become apparent under stressful conditions or when resistant and susceptible aphids are in direct competition. Understanding

Sugarcane Initial Growth with Vinasse Application in Latosol under Gradual Aluminum Stress

NASA Astrophysics Data System (ADS)

Marques Viglio, Larissa; Leal Varanda, Leticia; Soares, Marcio Roberto; Casagrande, José Carlos

2015-04-01

One of the strategies for overcoming the high acidity of soils and the consequent toxicity of aluminum (Al) is based on the use of varieties adapted to these conditions. In Brazil, the application of vinasse is routine practice in the cultivation of sugarcane due to its fertilizing effect, mainly because of high potassium content. However, the vinasse may also attenuate the toxic effects of Al in the soil by forming complexes with low molecular weight organic acids providing greater depth of the root of sugarcane. The aim of this work was to evaluate the effect of vinasse on the initial growth of three cultivars of sugarcane (RB855453, RB966928 and RB867515), as well as its influence on root depth in a Dystrophic Red-Yellow Latosol (Typic Hapludox) with gradient of saturation by Al. The experiment was conducted in a greenhouse, in totally randomized design with factorial arrangement and three replications. Seedlings of sugarcane were transplanted to PVC columns 0.8 m high, built by stacking four rings (0.2 m high), filled with soil samples, which offered an increasing gradient of saturation by Al (m%) at depth (0-0.2 m (m% = 0,7); 0.2-0.4 m (m% = 7,9); 0.4-0.6 m (m %= 40.8); 0.6-0.8 m (m%= 62.6)). The collection of the experiment was conducted 120 days after planting, with the determination of the stalk diameter (DC), plant height (ALT), leaf nutrient content, dry matter of the aerial part (MSPA) and dry matter of the root system (MSSR). Cultivars of sugarcane and the application of vinasse had effect on DC and the MSSR. Cultivar RB867515 showed higher DC than in other cultivars, with 20.8 mm. The increase of MSSR by sugarcane cultivars varied due to depth. There were no effects of sugarcane cultivars and vinasse application in MSPA. The vinasse application resulted in plants with higher ALT. With the exception of the foliar content of Fe, the N, Ca, Mg, S and Mn content were below those considered appropriate for sugarcane. Unlike other cultivars, the application

Specialization of bacterial endosymbionts that protect aphids from parasitoids

USDA-ARS?s Scientific Manuscript database

Infection by the bacterial endosymbiont HAMILTONELLA DEFENSA is capable of protecting the pea aphid from parasitism by APHIDIUS ERVI and the black bean aphid from parasitism by LYSIPHLEBUS FABARUM. Here we investigate protection of a third aphid species, the cowpea aphid, APHIS CRACCIVORA, from 4 p...

Do aphid colonies amplify their emission of alarm pheromone?

PubMed

Hatano, Eduardo; Kunert, Grit; Bartram, Stefan; Boland, Wilhelm; Gershenzon, Jonathan; Weisser, Wolfgang W

2008-09-01

When aphids are attacked by natural enemies, they emit alarm pheromone to alert conspecifics. For most aphids tested, (E)-beta-farnesene (EBF) is the main, or only, constituent of the alarm pheromone. In response to alarm pheromone, alerted aphids drop off the plant, walk away, or attempt to elude predators. However, under natural conditions, EBF concentration might be low due to the low amounts emitted, to rapid air movement, or to oxidative degradation. To ensure that conspecifics are warned, aphids might conceivably amplify the alarm signal by emitting EBF in response to EBF emitted by other aphids. To examine whether such amplification occurs, we synthesized deuterated EBF (DEBF), which allowed us to differentiate between applied and aphid-derived chemical. Colonies of Acyrthosiphon pisum were treated with DEBF, and headspace volatiles were collected and analyzed for evidence of aphid-derived EBF. No aphid-derived EBF was detected, suggesting that amplification of the alarm signal does not occur. We discuss the disadvantages of alarm signal reinforcement.

The Potato Aphid Salivary Effector Me47 Is a Glutathione-S-Transferase Involved in Modifying Plant Responses to Aphid Infestation.

PubMed

Kettles, Graeme J; Kaloshian, Isgouhi

2016-01-01

Polyphagous aphid pests cause considerable economic damage to crop plants, primarily through the depletion of photoassimilates and transfer of viruses. The potato aphid (Macrosiphum euphorbiae) is a notable pest of solanaceous crops, however, the molecular mechanisms that underpin the ability to colonize these hosts are unknown. It has recently been demonstrated that like other aphid species, M. euphorbiae injects a battery of salivary proteins into host plants during feeding. It is speculated that these proteins function in a manner analagous to secreted effectors from phytopathogenic bacteria, fungi and oomycetes. Here, we describe a novel aphid effector (Me47) which was identified from the potato aphid salivary secretome as a putative glutathione-S-transferase (GST). Expression of Me47 in Nicotiana benthamiana enhanced reproductive performance of green peach aphid (Myzus persicae). Similarly, delivery of Me47 into leaves of tomato (Solanum lycopersicum) by Pseudomonas spp. enhanced potato aphid fecundity. In contrast, delivery of Me47 into Arabidopsis thaliana reduced GPA reproductive performance, indicating that Me47 impacts the outcome of plant-aphid interactions differently depending on the host species. Delivery of Me47 by the non-pathogenic Pseudomonas fluorescens revealed that Me47 protein or activity triggers defense gene transcriptional upregulation in tomato but not Arabidopsis. Recombinant Me47 was purified and demonstrated to have GST activity against two specific isothiocyanates (ITCs), compounds implicated in herbivore defense. Whilst GSTs have previously been associated with development of aphid resistance to synthetic insecticides, the findings described here highlight a novel function as both an elicitor and suppressor of plant defense when delivered into host tissues.

The Potato Aphid Salivary Effector Me47 Is a Glutathione-S-Transferase Involved in Modifying Plant Responses to Aphid Infestation

PubMed Central

Kettles, Graeme J.; Kaloshian, Isgouhi

2016-01-01

Polyphagous aphid pests cause considerable economic damage to crop plants, primarily through the depletion of photoassimilates and transfer of viruses. The potato aphid (Macrosiphum euphorbiae) is a notable pest of solanaceous crops, however, the molecular mechanisms that underpin the ability to colonize these hosts are unknown. It has recently been demonstrated that like other aphid species, M. euphorbiae injects a battery of salivary proteins into host plants during feeding. It is speculated that these proteins function in a manner analagous to secreted effectors from phytopathogenic bacteria, fungi and oomycetes. Here, we describe a novel aphid effector (Me47) which was identified from the potato aphid salivary secretome as a putative glutathione-S-transferase (GST). Expression of Me47 in Nicotiana benthamiana enhanced reproductive performance of green peach aphid (Myzus persicae). Similarly, delivery of Me47 into leaves of tomato (Solanum lycopersicum) by Pseudomonas spp. enhanced potato aphid fecundity. In contrast, delivery of Me47 into Arabidopsis thaliana reduced GPA reproductive performance, indicating that Me47 impacts the outcome of plant–aphid interactions differently depending on the host species. Delivery of Me47 by the non-pathogenic Pseudomonas fluorescens revealed that Me47 protein or activity triggers defense gene transcriptional upregulation in tomato but not Arabidopsis. Recombinant Me47 was purified and demonstrated to have GST activity against two specific isothiocyanates (ITCs), compounds implicated in herbivore defense. Whilst GSTs have previously been associated with development of aphid resistance to synthetic insecticides, the findings described here highlight a novel function as both an elicitor and suppressor of plant defense when delivered into host tissues. PMID:27536306

Gene expression analysis of parthenogenetic embryonic development of the pea aphid, Acyrthosiphon pisum, suggests that aphid parthenogenesis evolved from meiotic oogenesis.

PubMed

Srinivasan, Dayalan G; Abdelhady, Ahmed; Stern, David L

2014-01-01

Aphids exhibit a form of phenotypic plasticity, called polyphenism, in which genetically identical females reproduce sexually during one part of the life cycle and asexually (via parthenogenesis) during the remainder of the life cycle. The molecular basis for aphid parthenogenesis is unknown. Cytological observations of aphid parthenogenesis suggest that asexual oogenesis evolved either through a modification of meiosis or from a mitotic process. As a test of these alternatives, we assessed the expression levels and expression patterns of canonical meiotic recombination and germline genes in the sexual and asexual ovaries of the pea aphid, Acyrthosiphon pisum. We observed expression of all meiosis genes in similar patterns in asexual and sexual ovaries, with the exception that some genes encoding Argonaute-family members were not expressed in sexual ovaries. In addition, we observed that asexual aphid tissues accumulated unspliced transcripts of Spo11, whereas sexual aphid tissues accumulated primarily spliced transcripts. In situ hybridization revealed Spo11 transcript in sexual germ cells and undetectable levels of Spo11 transcript in asexual germ cells. We also found that an obligately asexual strain of pea aphid produced little spliced Spo11 transcript. Together, these results suggest that parthenogenetic oogenesis evolved from a meiosis-like, and not a mitosis-like, process and that the aphid reproductive polyphenism may involve a modification of Spo11 gene activity.

Gene Expression Analysis of Parthenogenetic Embryonic Development of the Pea Aphid, Acyrthosiphon pisum, Suggests That Aphid Parthenogenesis Evolved from Meiotic Oogenesis

PubMed Central

Srinivasan, Dayalan G.; Abdelhady, Ahmed; Stern, David L.

2014-01-01

Aphids exhibit a form of phenotypic plasticity, called polyphenism, in which genetically identical females reproduce sexually during one part of the life cycle and asexually (via parthenogenesis) during the remainder of the life cycle. The molecular basis for aphid parthenogenesis is unknown. Cytological observations of aphid parthenogenesis suggest that asexual oogenesis evolved either through a modification of meiosis or from a mitotic process. As a test of these alternatives, we assessed the expression levels and expression patterns of canonical meiotic recombination and germline genes in the sexual and asexual ovaries of the pea aphid, Acyrthosiphon pisum. We observed expression of all meiosis genes in similar patterns in asexual and sexual ovaries, with the exception that some genes encoding Argonaute-family members were not expressed in sexual ovaries. In addition, we observed that asexual aphid tissues accumulated unspliced transcripts of Spo11, whereas sexual aphid tissues accumulated primarily spliced transcripts. In situ hybridization revealed Spo11 transcript in sexual germ cells and undetectable levels of Spo11 transcript in asexual germ cells. We also found that an obligately asexual strain of pea aphid produced little spliced Spo11 transcript. Together, these results suggest that parthenogenetic oogenesis evolved from a meiosis-like, and not a mitosis-like, process and that the aphid reproductive polyphenism may involve a modification of Spo11 gene activity. PMID:25501006

Spruce aphid (Elatobium abietinum Walker) (Hemiptera: Aphididae) [Chapter XXIV

Treesearch

Ann M. Lynch

2014-01-01

Elatobium abietinum Walker is a spruce-feeding aphid that in Europe is referred to as the green spruce aphid (Day et al., 1998a) (Fig. 1). However, in North America E. abietinum is known simply as the spruce aphid, while the common name "green spruce aphid" refers to a different species, Cinara fornacula Hottes (Hemiptera: Aphididae) (http://www.entsoc.org/...

The Nerium oleander aphid Aphis nerii is tolerant to a local isolate of Aphid lethal paralysis virus (ALPV).

PubMed

Dombrovsky, Aviv; Luria, Neta

2013-04-01

In a survey that was conducted during the year 2011, a local strain of Aphid lethal paralysis virus (ALPV) was identified and isolated from a wild population of Aphis nerii aphids living on Nerium oleander plants located in northern Israel. The new strain was tentatively named (ALPV-An). RNA extracted from the viral particles allowed the amplification and determination of the complete genome sequence. The virus genome is comprised of 9835 nucleotides. In a BLAST search analysis, the ALPV-An sequence showed 89 % nucleotide sequence identity with the whole genome of a South African ALPV and 96 and 94 % amino acid sequence identity with the ORF1 and ORF2 of that strain, respectively. In preliminary experiments, spray-applied, purified ALPV virions were highly pathogenic to the green peach aphid Myzus persicae; 95 % mortality was recorded 4 days post-infection. These preliminary results demonstrate the potential of ALPV for use as a biologic agent for some aphid control. Surprisingly, no visible ALPV pathogenic effects, such as morphological changes or paralysis, were observed in the A. nerii aphids infected with ALPV-An. The absence of clear ALPV symptoms in A. nerii led to the formulation of two hypotheses, which were partially examined in this study. The first hypothesis suggest that A. nerii is resistant or tolerant of ALPV, while the second hypothesis propose that ALPV-An may be a mild strain of ALPV. Currently, our results is in favor with the first hypothesis since ALPV-An is cryptic in A. nerii aphids and can be lethal for M. persicae aphids.

Both structural and non-structural forms of the readthrough protein of cucurbit aphid-borne yellows virus are essential for efficient systemic infection of plants.

PubMed

Boissinot, Sylvaine; Erdinger, Monique; Monsion, Baptiste; Ziegler-Graff, Véronique; Brault, Véronique

2014-01-01

Cucurbit aphid-borne yellows virus (CABYV) is a polerovirus (Luteoviridae family) with a capsid composed of the major coat protein and a minor component referred to as the readthrough protein (RT). Two forms of the RT were reported: a full-length protein of 74 kDa detected in infected plants and a truncated form of 55 kDa (RT*) incorporated into virions. Both forms were detected in CABYV-infected plants. To clarify the specific roles of each protein in the viral cycle, we generated by deletion a polerovirus mutant able to synthesize only the RT* which is incorporated into the particle. This mutant was unable to move systemically from inoculated leaves inferring that the C-terminal half of the RT is required for efficient long-distance transport of CABYV. Among a collection of CABYV mutants bearing point mutations in the central domain of the RT, we obtained a mutant impaired in the correct processing of the RT which does not produce the RT*. This mutant accumulated very poorly in upper non-inoculated leaves, suggesting that the RT* has a functional role in long-distance movement of CABYV. Taken together, these results infer that both RT proteins are required for an efficient CABYV movement.

Both Structural and Non-Structural Forms of the Readthrough Protein of Cucurbit aphid-borne yellows virus Are Essential for Efficient Systemic Infection of Plants

PubMed Central

Boissinot, Sylvaine; Erdinger, Monique; Monsion, Baptiste; Ziegler-Graff, Véronique; Brault, Véronique

2014-01-01

Cucurbit aphid-borne yellows virus (CABYV) is a polerovirus (Luteoviridae family) with a capsid composed of the major coat protein and a minor component referred to as the readthrough protein (RT). Two forms of the RT were reported: a full-length protein of 74 kDa detected in infected plants and a truncated form of 55 kDa (RT*) incorporated into virions. Both forms were detected in CABYV-infected plants. To clarify the specific roles of each protein in the viral cycle, we generated by deletion a polerovirus mutant able to synthesize only the RT* which is incorporated into the particle. This mutant was unable to move systemically from inoculated leaves inferring that the C-terminal half of the RT is required for efficient long-distance transport of CABYV. Among a collection of CABYV mutants bearing point mutations in the central domain of the RT, we obtained a mutant impaired in the correct processing of the RT which does not produce the RT*. This mutant accumulated very poorly in upper non-inoculated leaves, suggesting that the RT* has a functional role in long-distance movement of CABYV. Taken together, these results infer that both RT proteins are required for an efficient CABYV movement. PMID:24691251

The whole genome sequence assembly of the soybean aphid, Aphis glycines

USDA-ARS?s Scientific Manuscript database

Aphids are emerging as model organisms for both basic and applied research. Of the 5,000 estimated species, only two aphids have published whole genome sequences: the pea aphid Acyrthosiphon pisum, and the Russian wheat aphid, Diuraphis noxia. The soybean aphid (Aphis glycines) is an extreme special...

Aggressive mimicry coexists with mutualism in an aphid.

PubMed

Salazar, Adrián; Fürstenau, Benjamin; Quero, Carmen; Pérez-Hidalgo, Nicolás; Carazo, Pau; Font, Enrique; Martínez-Torres, David

2015-01-27

Understanding the evolutionary transition from interspecific exploitation to cooperation is a major challenge in evolutionary biology. Ant-aphid relationships represent an ideal system to this end because they encompass a coevolutionary continuum of interactions ranging from mutualism to antagonism. In this study, we report an unprecedented interaction along this continuum: aggressive mimicry in aphids. We show that two morphs clonally produced by the aphid Paracletus cimiciformis during its root-dwelling phase establish relationships with ants at opposite sides of the mutualism-antagonism continuum. Although one of these morphs exhibits the conventional trophobiotic (mutualistic) relationship with ants of the genus Tetramorium, aphids of the alternative morph are transported by the ants to their brood chamber and cared for as if they were true ant larvae. Gas chromatography-mass spectrometry analyses reveal that the innate cuticular hydrocarbon profile of the mimic morph resembles the profile of ant larvae more than that of the alternative, genetically identical nonmimic morph. Furthermore, we show that, once in the brood chamber, mimic aphids suck on ant larva hemolymph. These results not only add aphids to the limited list of arthropods known to biosynthesize the cuticular chemicals of their deceived hosts to exploit their resources but describe a remarkable case of plastic aggressive mimicry. The present work adds a previously unidentified dimension to the classical textbook paradigm of aphid-ant relationships by showcasing a complex system at the evolutionary interface between cooperation and exploitation.

Genome Sequence of the Pea Aphid Acyrthosiphon pisum

PubMed Central

2010-01-01

Aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. Here we present the 464 Mb draft genome assembly of the pea aphid Acyrthosiphon pisum. This first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. Pea aphids are host-plant specialists, they can reproduce both sexually and asexually, and they have coevolved with an obligate bacterial symbiont. Here we highlight findings from whole genome analysis that may be related to these unusual biological features. These findings include discovery of extensive gene duplication in more than 2000 gene families as well as loss of evolutionarily conserved genes. Gene family expansions relative to other published genomes include genes involved in chromatin modification, miRNA synthesis, and sugar transport. Gene losses include genes central to the IMD immune pathway, selenoprotein utilization, purine salvage, and the entire urea cycle. The pea aphid genome reveals that only a limited number of genes have been acquired from bacteria; thus the reduced gene count of Buchnera does not reflect gene transfer to the host genome. The inventory of metabolic genes in the pea aphid genome suggests that there is extensive metabolite exchange between the aphid and Buchnera, including sharing of amino acid biosynthesis between the aphid and Buchnera. The pea aphid genome provides a foundation for post-genomic studies of fundamental biological questions and applied agricultural problems. PMID:20186266

Companion Plants for Aphid Pest Management

PubMed Central

Ben-Issa, Refka; Gomez, Laurent; Gautier, Hélène

2017-01-01

A potential strategy for controlling pests is through the use of “companion plants” within a crop system. This strategy has been used in several trials to fight against a major crop insect pest: the aphid. We reviewed the literature to highlight the major mechanisms by which a companion plant may act. Trials carried out under laboratory or field conditions revealed that companion plants operate through several mechanisms. A companion plant may be associated with a target crop for various reasons. Firstly, it can attract aphids and draw them away from their host plants. Secondly, it can alter the recognition of the host plant. This effect is mostly attributed to companion plant volatiles since they disturb the aphid host plant location, and additionally they may react chemically and physiologically with the host plant, making it an unsuitable host for aphids. Thirdly, it can attract natural enemies by providing shelter and food resources. In this review, the feasibility of using companion plants is discussed. We conclude that many factors need to be taken into account for a successful companion plant strategy. For the best long-term results, companion plant strategies have to be combined with other alternative approaches against aphids. PMID:29053585

Role of the aphid species and their feeding locations in parasitization behavior of Aphelinus abdominalis, a parasitoid of the lettuce aphid Nasonovia ribisnigri

PubMed Central

Shrestha, Govinda; Skovgård, Henrik; Reddy, Gadi V. P.; Steenberg, Tove; Enkegaard, Annie

2017-01-01

Aphid species feeding on lettuce occupy distinct feeding sites: the lettuce aphid Nasonovia ribisnigri prefers to feed on heart leaves, whereas the potato aphid Macrosiphum euphorbiae feeds only on outer leaves. The aphid parasitoid Aphelinus abdominalis, known to be able to regulate M. euphorbiae on many crops, has recently been indicated as a promising biocontrol candidate also for use against N. ribisnigri, a major pest of lettuce. This study therefore examined A. abdominalis parasitization preference between N. ribisnigri and M. euphorbiae and its ability to parasitize aphids feeding on different parts of lettuce plants. In addition, life history traits of A. abdominalis on these aphid species were investigated. In no-choice laboratory experiments on leaf discs and 24 h exposure, A. abdominalis successfully parasitized 54% and 60% of the offered N. ribisnigri and M. euphorbiae, respectively, with no significant difference. In the corresponding choice experiment, however, A. abdominalis had a tendency for a significantly higher preference for M. euphorbiae (38%) compared to N. ribisnigri (30%). Growth chamber experiments on whole plants demonstrated that A. abdominalis was able to parasitize aphids, regardless of their feeding locations on lettuce plants. However, aphid feeding behavior had a significant effect on the parasitization rate. A. abdominalis parasitized significantly higher percentages of M. euphorbiae or N. ribisnigri when aphids were exposed separately to parasitoids on whole lettuce plants as compared with N. ribisnigri exposed only on heart leaf. A significant preference of A. abdominalis for M. euphorbiae compared to N. ribisnigri was also observed in the growth chamber choice experiment. A high percentage of adult emergence (> 84%) and female-biased sex ratio (> 83%) were found irrespective of the aphid species. PMID:28854232

Role of the aphid species and their feeding locations in parasitization behavior of Aphelinus abdominalis, a parasitoid of the lettuce aphid Nasonovia ribisnigri.

PubMed

Shrestha, Govinda; Skovgård, Henrik; Reddy, Gadi V P; Steenberg, Tove; Enkegaard, Annie

2017-01-01

Aphid species feeding on lettuce occupy distinct feeding sites: the lettuce aphid Nasonovia ribisnigri prefers to feed on heart leaves, whereas the potato aphid Macrosiphum euphorbiae feeds only on outer leaves. The aphid parasitoid Aphelinus abdominalis, known to be able to regulate M. euphorbiae on many crops, has recently been indicated as a promising biocontrol candidate also for use against N. ribisnigri, a major pest of lettuce. This study therefore examined A. abdominalis parasitization preference between N. ribisnigri and M. euphorbiae and its ability to parasitize aphids feeding on different parts of lettuce plants. In addition, life history traits of A. abdominalis on these aphid species were investigated. In no-choice laboratory experiments on leaf discs and 24 h exposure, A. abdominalis successfully parasitized 54% and 60% of the offered N. ribisnigri and M. euphorbiae, respectively, with no significant difference. In the corresponding choice experiment, however, A. abdominalis had a tendency for a significantly higher preference for M. euphorbiae (38%) compared to N. ribisnigri (30%). Growth chamber experiments on whole plants demonstrated that A. abdominalis was able to parasitize aphids, regardless of their feeding locations on lettuce plants. However, aphid feeding behavior had a significant effect on the parasitization rate. A. abdominalis parasitized significantly higher percentages of M. euphorbiae or N. ribisnigri when aphids were exposed separately to parasitoids on whole lettuce plants as compared with N. ribisnigri exposed only on heart leaf. A significant preference of A. abdominalis for M. euphorbiae compared to N. ribisnigri was also observed in the growth chamber choice experiment. A high percentage of adult emergence (> 84%) and female-biased sex ratio (> 83%) were found irrespective of the aphid species.

Effect of Sugarcane Mosaic caused by Sorghum mosaic virus on sugarcane in Louisiana

USDA-ARS?s Scientific Manuscript database

Sugarcane mosaic is caused by two viruses, Sugarcane mosaic virus (SCVM) or Sorghum mosaic virus (SrMV). In Louisiana, SrMV is the predominant mosaic pathogen affecting sugarcane. In a field experiment established in 2012, plots were planted with seed cane with or without mosaic symptoms. The mosaic...

Identification of Conditions for Successful Aphid Control by Ladybirds in Greenhouses

PubMed Central

Riddick, Eric W.

2017-01-01

As part of my research on the mass production and augmentative release of ladybirds, I reviewed the primary research literature to test the prediction that ladybirds are effective aphid predators in greenhouses. Aphid population reduction exceeded 50% in most studies and ladybird release rates usually did not correlate with aphid reduction. The ratio of aphid reduction/release rate was slightly less for larvae than adults in some studies, suggesting that larvae were less effective (than adults) in suppressing aphids. Some adult releases were inside cages, thereby limiting adult dispersion from plants. Overall, the ratio of aphid reduction/release rate was greatest for ladybird adults of the normal strain (several species combined), but least for adults of a flightless Harmonia axyridis strain. The combined action of ladybirds and hymenopteran parasitoids could have a net positive effect on aphid population suppression and, consequently, on host (crop) plants. However, ladybird encounters with aphid-tending or foraging ants must be reduced. Deploying ladybirds to help manage aphids in greenhouses and similar protective structures is encouraged. PMID:28350349

Aphid performance changes with plant defense mediated by Cucumber mosaic virus titer.

PubMed

Shi, Xiaobin; Gao, Yang; Yan, Shuo; Tang, Xin; Zhou, Xuguo; Zhang, Deyong; Liu, Yong

2016-04-22

Cucumber mosaic virus (CMV) causes appreciable losses in vegetables, ornamentals and agricultural crops. The green peach aphid, Myzus persicae Sulzer (Aphididae) is one of the most efficient vectors for CMV. The transmission ecology of aphid-vectored CMV has been well investigated. However, the detailed description of the dynamic change in the plant-CMV-aphid interaction associated with plant defense and virus epidemics is not well known. In this report, we investigated the relationship of virus titer with plant defense of salicylic acid (SA) and jasmonic acid (JA) during the different infection time and their interaction with aphids in CMV-infected tobacco plants. Our results showed that aphid performance changed with virus titer and plant defense on CMV-inoculated plants. At first, plant defense was low and aphid number increased gradually. The plant defense of SA signaling pathway was induced when virus titer was at a high level, and aphid performance was correspondingly reduced. Additionally, the winged aphids were increased. Our results showed that aphid performance was reduced due to the induced plant defense mediated by Cucumber mosaic virus titer. Additionally, some wingless aphids became to winged aphids. In this way CMV could be transmitted with the migration of winged aphids. We should take measures to prevent aphids in the early stage of their occurrence in the field to prevent virus outbreak.

Mapping soybean aphid resistance genes in PI 567598B

USDA-ARS?s Scientific Manuscript database

The soybean aphid (Aphis glycines Matsumura) has been a major pest of soybean [Glycine max (L.) Merr.] in North America since it was first discovered in 2000. Plant introduction PI 567598B possesses strong antibiosis resistance to soybean aphids. Our previous study revealed that the aphid resistan...

A single gene, AIN, in Medicago truncatula mediates a hypersensitive response to both bluegreen aphid and pea aphid, but confers resistance only to bluegreen aphid

PubMed Central

Klingler, John P.; Nair, Ramakrishnan M.; Edwards, Owain R.; Singh, Karam B.

2009-01-01

Biotic stress in plants frequently induces a hypersensitive response (HR). This distinctive reaction has been studied intensively in several pathosystems and has shed light on the biology of defence signalling. Compared with microbial pathogens, relatively little is known about the role of the HR in defence against insects. Reference genotype A17 of Medicago truncatula Gaertn., a model legume, responds to aphids of the genus Acyrthosiphon with necrotic lesions resembling a HR. In this study, the biochemical nature of this response, its mode of inheritance, and its relationship with defence against aphids were investigated. The necrotic lesion phenotype and resistance to the bluegreen aphid (BGA, Acyrthosiphon kondoi Shinji) and the pea aphid (PA, Acyrthosiphon pisum (Harris)) were analysed using reference genotypes A17 and A20, their F2 progeny and recombinant inbred lines. BGA-induced necrotic lesions co-localized with the production of H2O2, consistent with an oxidative burst widely associated with hypersensitivity. This HR correlated with stronger resistance to BGA in A17 than in A20; these phenotypes cosegregated as a semi-dominant gene, AIN (Acyrthosiphon-induced necrosis). In contrast to BGA, stronger resistance to PA in A17, compared with A20, did not cosegregate with a PA-induced HR. The AIN locus resides in a cluster of sequences predicted to encode the CC-NBS-LRR subfamily of resistance proteins. AIN-mediated resistance presents a novel opportunity to use a model plant and model aphid to study the role of the HR in defence responses to phloem-feeding insects. PMID:19690018

Field and laboratory evaluations of soybean lines against soybean aphid (Hemiptera: Aphididae).

PubMed

Hesler, Louis S; Prischmann, Deirdre A; Dashiell, Kenton E

2012-04-01

The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a major pest of soybean, Glycine max (L.). Merr., that significantly reduces yield in northern production areas of North America. Insecticides are widely used to control soybean aphid outbreaks, but efforts are underway to develop host plant resistance as an effective alternative management strategy. Here, previously identified resistant lines were evaluated in laboratory tests against field-collected populations of soybean aphid and in field-plot tests over 2 yr in South Dakota. Six lines previously identified with resistance to soybean aphid--Jackson, Dowling, K1639, Cobb, Palmetto and Sennari--were resistant in this study, but relatively high aphid counts on Tie-feng 8 in field plots contrasted with its previously reported resistance. Bhart-PI 165989 showed resistance in one of two laboratory tests, but it had relatively large aphid infestations in both years of field tests. Intermediate levels of soybean aphid occurred in field plots on lines previously shown to have strong (Sugao Zairai, PI 230977, and D75-10169) or moderate resistance to soybean aphid (G93-9223, Bragg, Braxton, and Tracy-M). Sugao Zairai also failed to have a significant proportion of resistant plants in two laboratory tests against aphids field-collected in 2008, but it was resistant in laboratory tests with aphids collected in 2002, 2005, and 2006. Overall, results showed that lines with Rag (i.e., Jackson) or Rag1 gene (i.e., Dowling) had low aphid numbers, whereas lines with Rag2 (i.e., Sugao Zairai, Sennari) had mixed results. Collectively, responses of soybean aphid populations in laboratory and field tests in 2008 resembled a virulence pattern reported previously for biotype 3 soybean aphids, but virulence in soybean aphid populations was variable and dynamic over years of the study. These results, coupled with previous reports of biotypes virulent to Rag1, suggest that deployment of lines with a single aphid

Aphid Species Affect Foraging Behavior of Coccinella septempunctata (Coccinellidae: Coleoptera).

PubMed

Farooq, Muhammad Umar; Qadri, Hafiz Faqir Hussain; Khan, Muhammad Ahmad

2017-01-01

Flowers are admirable in scenic good looks and artistic beautification. These are also playing necessary roles in therapeutic preparations. Aphid is an important sucking pest of various flowers in ornamental territories and it is generally controlled by predators, so it was necessary to evaluate which aphid species affect the predator more or less. Biocontrol agent Coccinella septempunctata was used against cosmos aphid (Aphis spiraecola, rose aphid (Macrosiphum rosea), gul e ashrafi aphid (Aphis fabae), kaner aphid (Aphis nerii), chandni aphid (Sitobion avenae), dahlia aphid (Myzus persicae) and annual chrysanthemum aphid (Macrosiphoniella sanborni). The grub of C. septempunctata consumed 283.8±9.04 M. rosea, 487.7±12.6 M. sanborni, 432.75±16.02 A. spiraecola, 478.2±8.07 A. fabae, 552.3±9.04 M. persicae, 142±1.32 A. nerii and 498.5±13.09 S. avenae in its whole larval life. The M. persicae and M. rosea consuming grubs showed 100% adult emergence while, M. sanborni, A. spiraecola, A. fabae and S. avenae showed 96.58, 89.02, 94.78 and 75.45% adult emergence, respectively. The C. septempunctata has significant predatory potential against A. spiraecola, M. rosea, A. fabae, S. avenae, M. persicae and M. sanborni except A. nerii. Thus, further studies are needed to find out alternate predator to control A. nerii on ornamentals.

Sugarcane-Biorefinery.

PubMed

Vaz, Sílvio

2017-03-17

Concepts such as biorefinery and green chemistry focus on the usage of biomass, as with the oil value chain. However, it can cause less negative impact on the environment. A biorefinery based on sugarcane (Saccharum spp.) as feedstock is an example, because it can integrate into the same physical space, of processes for obtaining biofuels (ethanol), chemicals (from sugars or ethanol), electricity, and heat.The use of sugarcane as feedstock for biorefineries is dictated by its potential to supply sugars, ethanol, natural polymers or macromolecules, organic matter, and other compounds and materials. By means of conversion processes (chemical, biochemical, and thermochemical), sugarcane biomass can be transformed into high-value bioproducts to replace petrochemicals, as a bioeconomy model.

Terpenoid biosynthesis in Arabidopsis attacked by caterpillars and aphids: effects of aphid density on the attraction of a caterpillar parasitoid.

PubMed

Kroes, Anneke; Weldegergis, Berhane T; Cappai, Francesco; Dicke, Marcel; van Loon, Joop J A

2017-12-01

One of the responses of plants to insect attack is the production of volatile organic compounds that mediate indirect defence of plants by attracting natural enemies of the attacking herbivores. Herbivore-induced plant volatiles (HIPVs) include terpenoids that play key roles in the attraction of natural enemies. Crosstalk between phytohormonal signalling pathways is well known to affect the regulation of plant defences, including the emission of HIPVs. Thus, simultaneous feeding on the same plant by caterpillars and aphids, can affect the attraction of parasitoids by the plant compared to single insect attack. The role of aphid density in the regulation of HIPV emission by plants under dual attack has not been studied previously. Here, we investigated the attraction of Diadegma semiclausum, a parasitoid of the Diamondback moth Plutella xylostella, to volatiles emitted by Arabidopsis thaliana plants, simultaneously attacked by host caterpillars, and by the non-host aphid Brevicoryne brassicae. Our study shows that the effect of aphid infestation on parasitoid attraction is influenced by the density of the aphids. Biosynthesis and emission of (E,E)-α-farnesene could be linked to the observed preference of D. semiclausum parasitoids for the HIPV blend emitted by plants dually infested by caterpillars and aphids at a high density compared to dually infested plants with a low aphid density. Parasitoids such as D. semiclausum are important enemies of herbivorous insects and a better understanding of how plants express indirect defence mechanisms in response to multiple insect attack will provide important knowledge on plant-herbivore-parasitoid interactions under multiple stress conditions.

Transparency Master: The Annual Aphid Cycle.

ERIC Educational Resources Information Center

Sessions, Mary Lynne

1983-01-01

Aphids, often referred to as plant lice, can be found in great numbers on stems, leaves, and flowers of many plants. In many cases these organisms are potentially harmful to their plant hosts. Provided is a description of the annual life cycle of the aphid and an accompanying transparency master. (Author/JN)

Stem nematode counteracts plant resistance of aphids in alfalfa, Medicago sativa.

PubMed

Ramirez, Ricardo A; Spears, Lori R

2014-10-01

Plants are exploited by a diverse community of insect herbivores and phytopathogens that interact indirectly through plant-mediated interactions. Generally, plants are thought to respond to insects and pathogens through different defensive signaling pathways. As plants are selected for resistance to one phytophagous organism type (insect vs. pathogen) in managed systems, it is not clear how this selection may affect community interactions. This study examined the effect of nematode-resistant varieties on aphid (Acyrthosiphon pisum) suppression, and then determined how infection by the stem nematode, Ditylenchus dipsaci, mediated ecological effects on aphids and on plant defense proteins. Four alfalfa (Medicago sativa) varieties were selected with resistance to nematodes only (+,-), aphids only (-,+), nematodes and aphids (+,+), and susceptibility to nematodes and aphids (-,-). Field and greenhouse experiments were conducted to isolate the effect of nematode infection and aphid abundance on each variety. We found that varieties resistant to nematode, regardless of aphid resistance, had the lowest aphid counts, suggesting possible cross-resistance. Aphid abundance, however, increased when plants were exposed to nematodes. Resistant varieties were associated with elevated saponins but these compounds were not affected by insect or pathogen feeding. Concentrations of peroxidases and trypsin inhibitors, however, were increased in nematode resistant varieties when exposed to nematodes and aphids, respectively. The patterns of plant defense were variable, and a combination of resistance traits and changes in nutrient availability may drive positive interactions between nematodes and aphids aboveground.

Elevated atmospheric carbon dioxide concentrations promote ant tending of aphids.

PubMed

Kremer, Jenni M M; Nooten, Sabine S; Cook, James M; Ryalls, James M W; Barton, Craig V M; Johnson, Scott N

2018-04-27

Animal mutualisms, which involve beneficial interactions between individuals of different species, are common in nature. Insect-insect mutualism, for example, is widely regarded as a keystone ecological interaction. Some mutualisms are anticipated to be modified by climate change, but the focus has largely been on plant-microbe and plant-animal mutualisms rather than those between animals. Ant-aphid mutualisms, whereby ants tend aphids to harvest their honeydew excretions and, in return, provide protection for the aphids, are widespread. The mutualism is heavily influenced by the quality and quantity of honeydew produced by aphids, which is directly affected by host plant quality. As predicted increases in concentrations of atmospheric carbon dioxide (eCO 2 ) are widely reported to affect plant nutritional chemistry, this may also alter honeydew quality and hence the nature of ant-aphid mutualisms. Using glasshouse chambers and field-based open-top chambers, we determined the effect of eCO 2 on the growth and nutritional quality (foliar amino acids) of lucerne (Medicago sativa). We determined how cowpea aphid (Aphis craccivora) populations and honeydew production were impacted when feeding on such plants and how this affected the tending behaviour of ants (Iridomyrmex sp.). eCO 2 stimulated plant growth but decreased concentrations of foliar amino acids by 29% and 14% on aphid-infested plants and aphid-free plants, respectively. Despite the deterioration in host plant quality under eCO 2 , aphids maintained performance and populations were unchanged by eCO 2 . Aphids induced higher concentrations of amino acids (glutamine, asparagine, glutamic acid and aspartic acid) important for endosymbiont-mediated synthesis of essential amino acids. Aphids feeding under eCO 2 also produced over three times more honeydew than aphids feeding under ambient CO 2 , suggesting they were imbibing more phloem sap at eCO 2 . The frequency of ant tending of aphids more than doubled in

Integrative proteomics to understand the transmission mechanism of Barley yellow dwarf virus-GPV by its insect vector Rhopalosiphum padi

PubMed Central

Wang, Hui; Wu, Keke; Liu, Yan; Wu, Yunfeng; Wang, Xifeng

2015-01-01

Barley yellow dwarf virus-GPV (BYDV-GPV) is transmitted by Rhopalosiphum padi and Schizaphis graminum in a persistent nonpropagative manner. To improve our understanding of its transmission mechanism by aphid vectors, we used two approaches, isobaric tags for relative and absolute quantitation (iTRAQ) and yeast two-hybrid (YTH) system, to identify proteins in R. padi that may interact with or direct the spread of BYDV-GPV along the circulative transmission pathway. Thirty-three differential aphid proteins in viruliferous and nonviruliferous insects were identified using iTRAQ coupled to 2DLC-MS/MS. With the yeast two-hybrid system, 25 prey proteins were identified as interacting with the readthrough protein (RTP) and eight with the coat protein (CP), which are encoded by BYDV-GPV. Among the aphid proteins identified, most were involved in primary energy metabolism, synaptic vesicle cycle, the proteasome pathway and the cell cytoskeleton organization pathway. In a systematic comparison of the two methods, we found that the information generated by the two methods was complementary. Taken together, our findings provide useful information on the interactions between BYDV-GPV and its vector R. padi to further our understanding of the mechanisms regulating circulative transmission in aphid vectors. PMID:26161807

Virulent Diuraphis noxia Aphids Over-Express Calcium Signaling Proteins to Overcome Defenses of Aphid-Resistant Wheat Plants

PubMed Central

Sinha, Deepak K.; Chandran, Predeesh; Timm, Alicia E.; Aguirre-Rojas, Lina; Smith, C. Michael

2016-01-01

The Russian wheat aphid, Diuraphis noxia, an invasive phytotoxic pest of wheat, Triticum aestivum, and barley, Hordeum vulgare, causes huge economic losses in Africa, South America, and North America. Most acceptable and ecologically beneficial aphid management strategies include selection and breeding of D. noxia-resistant varieties, and numerous D. noxia resistance genes have been identified in T. aestivum and H. vulgare. North American D. noxia biotype 1 is avirulent to T. aestivum varieties possessing Dn4 or Dn7 genes, while biotype 2 is virulent to Dn4 and avirulent to Dn7. The current investigation utilized next-generation RNAseq technology to reveal that biotype 2 over expresses proteins involved in calcium signaling, which activates phosphoinositide (PI) metabolism. Calcium signaling proteins comprised 36% of all transcripts identified in the two D. noxia biotypes. Depending on plant resistance gene-aphid biotype interaction, additional transcript groups included those involved in tissue growth; defense and stress response; zinc ion and related cofactor binding; and apoptosis. Activation of enzymes involved in PI metabolism by D. noxia biotype 2 aphids allows depletion of plant calcium that normally blocks aphid feeding sites in phloem sieve elements and enables successful, continuous feeding on plants resistant to avirulent biotype 1. Inhibition of the key enzyme phospholipase C significantly reduced biotype 2 salivation into phloem and phloem sap ingestion. PMID:26815857

Proteomic Investigation of Aphid Honeydew Reveals an Unexpected Diversity of Proteins

PubMed Central

Haubruge, Eric; Hance, Thierry; Thonart, Philippe; De Pauw, Edwin; Francis, Frédéric

2013-01-01

Aphids feed on the phloem sap of plants, and are the most common honeydew-producing insects. While aphid honeydew is primarily considered to comprise sugars and amino acids, its protein diversity has yet to be documented. Here, we report on the investigation of the honeydew proteome from the pea aphid Acyrthosiphon pisum. Using a two-Dimensional Differential in-Gel Electrophoresis (2D-Dige) approach, more than 140 spots were isolated, demonstrating that aphid honeydew also represents a diverse source of proteins. About 66% of the isolated spots were identified through mass spectrometry analysis, revealing that the protein diversity of aphid honeydew originates from several organisms (i.e. the host aphid and its microbiota, including endosymbiotic bacteria and gut flora). Interestingly, our experiments also allowed to identify some proteins like chaperonin, GroEL and Dnak chaperones, elongation factor Tu (EF-Tu), and flagellin that might act as mediators in the plant-aphid interaction. In addition to providing the first aphid honeydew proteome analysis, we propose to reconsider the importance of this substance, mainly acknowledged to be a waste product, from the aphid ecology perspective. PMID:24086359

Sugarcane Improvement Through Breeding and Biotechnology

USDA-ARS?s Scientific Manuscript database

The advancements in sugarcane breeding and the improvement of sugarcane through biotechnology have been reviewed by a team of leading sugarcane specialists from around the world. Topics covered in the breeding section include the evolution and origin of sugarcane, early history of conventional sugar...

Secondary bacterial symbiont community in aphids responds to plant diversity.

PubMed

Zytynska, Sharon E; Meyer, Sebastian T; Sturm, Sarah; Ullmann, Wiebke; Mehrparvar, Mohsen; Weisser, Wolfgang W

2016-03-01

Biodiversity is important for ecosystem functioning and biotic interactions. In experimental grasslands, increasing plant species richness is known to increase the diversity of associated herbivores and their predators. If these interactions can also involve endosymbionts that reside within a plant or animal host is currently unknown. In plant-feeding aphids, secondary bacterial symbionts can have strong fitness effects on the host, e.g. resistance to natural enemies or fungal pathogens. We examined the secondary symbiont community in three species of aphid, each feeding on a unique host plant across experimental plots that varied in plant species richness. Aphids were collected in May and June, and the symbiont community identified using species-specific PCR assays. Aphis fabae aphids were found to host six different symbiont species with individual aphids co-hosting up to four symbionts. Uroleucon jaceae and Macrosiphum rosae hosted two and three symbiont species, respectively. We found that, at the aphid population level, increasing plant species richness increased the diversity of the aphid symbiont community, whereas at the individual aphid level, the opposite was found. These effects are potentially driven by varying selective pressures across different plant communities of varying diversities, mediated by defensive protection responses and a changing cost-benefit trade-off to the aphid for hosting multiple secondary symbionts. Our work extends documented effects of plant diversity beyond visible biotic interactions to changes in endosymbiont communities, with potentially far-reaching consequences to related ecosystem processes.

Determination of flavonoids in cultivated sugarcane leaves, bagasse, juice and in transgenic sugarcane by liquid chromatography-UV detection.

PubMed

Colombo, Renata; Lanças, Fernando M; Yariwake, Janete H

2006-01-20

A high-performance liquid chromatography (HPLC) method with photo-diode array (DAD) detection was developed to separate and quantify flavonoids in sugarcane leaves and bagasse (= the crushed sugarcane refuse from juice extraction), and in sugarcane juice. Sugarcane flavonoids consist of a complex mixture of aglycones and glycosides (including flavonolignan glycosides), and the HPLC-UV method herein proposed is suitable for their quantification as total flavonoids. This method was applied to analyze samples of cultivated sugarcane, commercial juice and transgenic sugarcane leaves. Sugarcane leaves proved a promising source of flavonoids: an average of 1.10 mg of total flavonoids/g plant material was found in fresh leaves. Moreover, the flavonoid content of sugarcane juice (0.6 mg/mL) is comparable to other food sources of flavonoids previously reported. Transgenic sugarcane leaves ("Bowman-Birk" and "Kunitz") were compared with non-modified ("control") plant samples using the proposed HPLC-UV method, which indicated that the content of total flavonoids in transgenic plants is different from that in non-modified sugarcane.

A highly infective plant-associated bacterium influences reproductive rates in pea aphids

PubMed Central

Hendry, Tory A.; Clark, Kelley J.; Baltrus, David A.

2016-01-01

Pea aphids, Acyrthosiphon pisum, have the potential to increase reproduction as a defence against pathogens, though how frequently this occurs or how infection with live pathogens influences this response is not well understood. Here we determine the minimum infective dose of an environmentally common bacterium and possible aphid pathogen, Pseudomonas syringae, to determine the likelihood of pathogenic effects to pea aphids. Additionally, we used P. syringae infection to investigate how live pathogens may alter reproductive rates. We found that oral bacterial exposure decreased subsequent survival of aphids in a dose-dependent manner and we estimate that ingestion of less than 10 bacterial cells is sufficient to increase aphid mortality. Pathogen dose was positively related to aphid reproduction. Aphids exposed to low bacterial doses showed decreased, although statistically indistinguishable, fecundity compared to controls. Aphids exposed to high doses reproduced significantly more than low dose treatments and also more, but not significantly so, than controls. These results are consistent with previous studies suggesting that pea aphids may use fecundity compensation as a response to pathogens. Consequently, even low levels of exposure to a common plant-associated bacterium may therefore have significant effects on pea aphid survival and reproduction. PMID:26998321

A highly infective plant-associated bacterium influences reproductive rates in pea aphids.

PubMed

Hendry, Tory A; Clark, Kelley J; Baltrus, David A

2016-02-01

Pea aphids, Acyrthosiphon pisum, have the potential to increase reproduction as a defence against pathogens, though how frequently this occurs or how infection with live pathogens influences this response is not well understood. Here we determine the minimum infective dose of an environmentally common bacterium and possible aphid pathogen, Pseudomonas syringae, to determine the likelihood of pathogenic effects to pea aphids. Additionally, we used P. syringae infection to investigate how live pathogens may alter reproductive rates. We found that oral bacterial exposure decreased subsequent survival of aphids in a dose-dependent manner and we estimate that ingestion of less than 10 bacterial cells is sufficient to increase aphid mortality. Pathogen dose was positively related to aphid reproduction. Aphids exposed to low bacterial doses showed decreased, although statistically indistinguishable, fecundity compared to controls. Aphids exposed to high doses reproduced significantly more than low dose treatments and also more, but not significantly so, than controls. These results are consistent with previous studies suggesting that pea aphids may use fecundity compensation as a response to pathogens. Consequently, even low levels of exposure to a common plant-associated bacterium may therefore have significant effects on pea aphid survival and reproduction.

Evolutionary ecology of the interactions between aphids and their parasitoids.

PubMed

Le Ralec, Anne; Anselme, Caroline; Outreman, Yannick; Poirié, Marylène; van Baaren, Joan; Le Lann, Cécile; van Alphen, Jacques J-M

2010-01-01

Many organisms, including entomopathogenous fungi, predators or parasites, use aphids as ressources. Parasites of aphids are mostly endoparasitoid insects, i.e. insects which lay eggs inside the body of an other insect which will die as a result of their development. In this article, we review the consequences of the numerous pecularities of aphid biology and ecology for their endoparasitoids, notably the Aphidiinae (Hymenoptera: Braconidae). We first examine the various mechanisms used by aphids for defence against these enemies. We then explore the strategies used by aphidiine parasitoids to exploit their aphid hosts. Finally, we consider the responses of both aphids and parasitoids to ecological constraints induced by seasonal cycles and to environmental variations linked to host plants and climate. The fundamental and applied interest of studying these organisms is discussed. Copyright 2010 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Demography of soybean aphid (Homoptera: Aphididae) at summer temperatures.

PubMed

McCornack, B P; Ragsdale, D W; Venette, R C

2004-06-01

Soybean aphid, Aphis glycines Matsumura, is now widely established in soybean, Glycine max L., production areas of the northern United States and southern Canada and is becoming an important economic pest. Temperature effect on soybean aphid fecundity and survivorship is not well understood. We determined the optimal temperature for soybean aphid growth and reproduction on soybean under controlled conditions. We constructed life tables for soybean aphid at 20, 25, 30, and 35 degrees C with a photoperiod of 16:8 (L:D) h. Population growth rates were greatest at 25 degrees C. As temperature increased, net fecundity, gross fecundity, generation time, and life expectancy decreased. The prereproductive period did not differ between 20 and 30 degrees C; however, at 30 degrees C aphids required more degree-days (base 8.6 degrees C) to develop. Nymphs exposed to 35 degrees C did not complete development, and all individuals died within 11 d. Reproductive periods were significantly different at all temperatures, with aphids reproducing longer and producing more progeny at 20 and 25 degrees C than at 30 or 35 degrees C. Using a modification of the nonlinear Logan model, we estimated upper and optimal developmental thresholds to be 34.9 and 27.8 degrees C, respectively. At 25 degrees C, aphid populations doubled in 1.5 d; at 20 and 30 degrees C, populations doubled in 1.9 d.

National Plant Diagnostic Network, Taxonomic training videos: Introduction to Aphids - Part 2

USDA-ARS?s Scientific Manuscript database

Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides visual instruction on important subject areas for aphid regulatory issues. Here the subject of aphids as they relate to disease transmission, biology, identification, and pathways is addressed. Aphid topi...

Ethanol production potential from AFEX™ and steam-exploded sugarcane residues for sugarcane biorefineries.

PubMed

Mokomele, Thapelo; da Costa Sousa, Leonardo; Balan, Venkatesh; van Rensburg, Eugéne; Dale, Bruce E; Görgens, Johann F

2018-01-01

Expanding biofuel markets are challenged by the need to meet future biofuel demands and mitigate greenhouse gas emissions, while using domestically available feedstock sustainably. In the context of the sugar industry, exploiting under-utilized cane leaf matter (CLM) in addition to surplus sugarcane bagasse as supplementary feedstock for second-generation ethanol production has the potential to improve bioenergy yields per unit land. In this study, the ethanol yields and processing bottlenecks of ammonia fibre expansion (AFEX™) and steam explosion (StEx) as adopted technologies for pretreating sugarcane bagasse and CLM were experimentally measured and compared for the first time. Ethanol yields between 249 and 256 kg Mg -1 raw dry biomass (RDM) were obtained with AFEX™-pretreated sugarcane bagasse and CLM after high solids loading enzymatic hydrolysis and fermentation. In contrast, StEx-pretreated sugarcane bagasse and CLM resulted in substantially lower ethanol yields that ranged between 162 and 203 kg Mg -1 RDM. The ethanol yields from StEx-treated sugarcane residues were limited by the aggregated effect of sugar degradation during pretreatment, enzyme inhibition during enzymatic hydrolysis and microbial inhibition of S. cerevisiae 424A (LNH-ST) during fermentation. However, relatively high enzyme dosages (> 20 mg g -1 glucan) were required irrespective of pretreatment method to reach 75% carbohydrate conversion, even when optimal combinations of Cellic ® CTec3, Cellic ® HTec3 and Pectinex Ultra-SP were used. Ethanol yields per hectare sugarcane cultivation area were estimated at 4496 and 3416 L ha -1 for biorefineries using AFEX™- or StEx-treated sugarcane residues, respectively. AFEX™ proved to be a more effective pretreatment method for sugarcane residues relative to StEx due to the higher fermentable sugar recovery and enzymatic hydrolysate fermentability after high solids loading enzymatic hydrolysis and fermentation by S. cerevisiae 424A

Molecular diversity of poleroviruses infecting cucurbit crops in four countries reveals the presence of members of six distinct species.

PubMed

Knierim, D; Tsai, W S; Maiss, E; Kenyon, L

2014-06-01

When 66 cucurbit samples with yellowing symptoms from fields in Mali, the Philippines, Thailand and Uzbekistan were screened by RT-PCR using universal polerovirus primers, 21 were identified as harboring polerovirus RNA. When these 21 samples were screened with specific primers for the known cucurbit-infecting poleroviruses, suakwa aphid-borne yellows virus and a recombinant strain of cucurbit aphid-borne yellows virus were detected for the first time in the Philippines and Thailand. However, seven polerovirus-positive samples did not react with any of the known species-specific primers. Sequencing of 1.4-kb universal polerovirus RT-PCR products revealed the presence of two poleroviruses that had not been described previously. These viruses, from Mali and Thailand, were provisionally named pepo aphid-borne yellows virus and luffa aphid-borne yellows virus, respectively.

Tetramorium tsushimae Ants Use Methyl Branched Hydrocarbons of Aphids for Partner Recognition.

PubMed

Sakata, Itaru; Hayashi, Masayuki; Nakamuta, Kiyoshi

2017-10-01

In mutualisms, partner discrimination is often the most important challenge for interacting organisms. The interaction between ants and aphids is a model system for studying mutualisms; ants are provided with honeydew by aphids and, in turn, the ants offer beneficial services to the aphids. To establish and maintain this system, ants must discriminate mutualistic aphid species correctly. Although recent studies have shown that ants recognize aphids as mutualistic partners based on their cuticular hydrocarbons (CHCs), it was unclear which CHCs are involved in recognition. Here, we tested whether the n-alkane or methylalkane fraction, or both, of aphid CHCs were utilized as partner recognition cues by measuring ant aggressiveness toward these fractions. When workers of Tetramorium tsushimae ants were presented with dummies coated with n-alkanes of their mutualistic aphid Aphis craccivora, ants displayed higher levels of aggression than to dummies treated with total CHCs or methyl alkanes of A. craccivora; responses to dummies treated with n-alkanes of A. craccivora were similar to those to control dummies or dummies treated with the CHCs of the non-mutualistic aphid Acyrthosiphon pisum. By contrast, ants exhibited lower aggression to dummies treated with either total CHCs or the methylalkane fraction of the mutualistic aphid than to control dummies or dummies treated with CHCs of the non-mutualistic aphid. These results suggest that T. tsushimae ants use methylalkanes of the mutualistic aphid's CHCs to recognize partners, and that these ants do not recognize aphids as partners on the basis of n-alkanes.

Activation of defence in sweet pepper, Capsicum annum, by cis-jasmone, and its impact on aphid and aphid parasitoid behaviour.

PubMed

Dewhirst, Sarah Y; Birkett, Michael A; Loza-Reyes, Elisa; Martin, Janet L; Pye, Barry J; Smart, Lesley E; Hardie, Jim; Pickett, John A

2012-10-01

Two important pests of the sweet pepper, Capsicum annuum, are the peach potato aphid, Myzus persicae, and the glasshouse potato aphid, Aulacorthum solani. Current aphid control measures include the use of biological control agents, i.e., parasitic wasps, but with varying levels of success. One option to increase parasitoid efficiency is to activate plant defence. Therefore, sweet pepper plants were treated with the naturally occurring plant defence activator cis-jasmone, and its impact upon the behaviour and development of aphids and aphid parasitoids was investigated. Growth rate studies revealed that the intrinsic rate of population increase of A. solani and M. persicae on sweet pepper plants treated with cis-jasmone (cJSP) was not affected compared with untreated plants (UnSP), but the positive behavioural response of alate M. persicae towards the volatile organic compounds (VOCs) from UnSP was eliminated by cis-jasmone treatment 48 h previously (cJSP48). In addition, the aphid parasitoid Aphidius ervi preferred VOCs from cJSP48 compared with UnSP, and a significant increase in foraging time was also observed on cJSP. Analysis of VOCs collected from cJSP48 revealed differences compared with UnSP. There is evidence that treatment with cis-jasmone has the potential to improve protection of sweet pepper against insect pests. © Crown copyright 2012. Reproduced with permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.

Aphid facultative symbionts reduce survival of the predatory lady beetle Hippodamia convergens

PubMed Central

2014-01-01

Background Non-essential facultative endosymbionts can provide their hosts with protection from parasites, pathogens, and predators. For example, two facultative bacterial symbionts of the pea aphid (Acyrthosiphon pisum), Serratia symbiotica and Hamiltonella defensa, protect their hosts from parasitism by two species of parasitoid wasp. Previous studies have not explored whether facultative symbionts also play a defensive role against predation in this system. We tested whether feeding on aphids harboring different facultative symbionts affected the fitness of an aphid predator, the lady beetle Hippodamia convergens. Results While these aphid faculative symbionts did not deter lady beetle feeding, they did decrease survival of lady beetle larvae. Lady beetle larvae fed a diet of aphids with facultative symbionts had significantly reduced survival from egg hatching to pupation and therefore had reduced survival to adult emergence. Additionally, lady beetle adults fed aphids with facultative symbionts were significantly heavier than those fed facultative symbiont-free aphids, though development time was not significantly different. Conclusions Aphids reproduce clonally and are often found in large groups. Thus, aphid symbionts, by reducing the fitness of the aphid predator H. convergens, may indirectly defend their hosts’ clonal descendants against predation. These findings highlight the often far-reaching effects that symbionts can have in ecological systems. PMID:24555501

Alternative cropping systems for sugarcane

USDA-ARS?s Scientific Manuscript database

Planting cover crops during the fallow period prior to planting sugarcane has the potential to influence not only the following sugarcane crop, but the economics of the production system as a whole. Research was conducted at the USDA, ARS, Sugarcane Research Unit at Houma, LA to determine the impac...

Ants Learn Aphid Species as Mutualistic Partners: Is the Learning Behavior Species-Specific?

PubMed

Hayashi, Masayuki; Nakamuta, Kiyoshi; Nomura, Masashi

2015-12-01

In ant-aphid associations, many aphid species provide ants with honeydew and are tended by ants, whereas others are never tended and are frequently preyed upon by ants. In these relationships, ants must have the ability to discriminate among aphid species, with mutualistic aphids being accepted as partners rather than prey. Although ants reportedly use cuticular hydrocarbons (CHCs) of aphids to differentiate between mutualistic and non-mutualistic species, it is unclear whether the ability to recognize mutualistic aphid species as partners is innate or involves learning. Therefore, we tested whether aphid recognition by ants depends on learning, and whether the learning behavior is species-specific. When workers of the ant Tetramorium tsushimae had previously tended the cowpea aphid, Aphis craccivora, they were less aggressive toward this species. In addition, ants also reduced their aggressiveness toward another mutualistic aphid species, Aphis fabae, after tending A. craccivora, whereas ants remained aggressive toward the non-mutualistic aphid, Acyrthosiphon pisum, regardless of whether or not they had previous experience in tending A. craccivora. When ants were offered glass dummies treated with CHCs of these aphid species, ants that had tended A. craccivora displayed reduced aggression toward CHCs of A. craccivora and A. fabae. Chemical analyses showed the similarity of the CHC profiles between A. craccivora and A. fabae but not with A. pisum. These results suggest that aphid recognition of ants involves learning, and that the learning behavior may not be species-specific because of the similarity of CHCs between different aphid species with which they form mutualisms.

Sugarcane and Energycane

USDA-ARS?s Scientific Manuscript database

“Energycane” is a term that is used to describe sugarcane grown solely for the production of renewable energy. A Type I energycane has somewhat lower sugar content (10-14%) and higher fiber content (14-20%) than a commercial sugarcane cultivar bred for sugar production. In contrast, a Type II energy...

Rag Virulence Among Soybean Aphids (Hemiptera: Aphididae) in Wisconsin.

PubMed

Crossley, Michael S; Hogg, David B

2015-02-01

Soybean aphid, Aphis glycines Matsumura, a pest of soybean, Glycine max (L.) Merr., and native of Asia, invaded North America sometime before 2000 and rapidly became the most significant insect pest of soybean in the upper Midwest. Plant resistance, a key component of integrated pest management, has received significant attention in the past decade, and several resistance (Rag) genes have been identified. However, the efficacy of Rag (Resistance to Aphis glycines) genes in suppressing aphid abundance has been challenged by the occurrence of soybean aphids capable of overcoming Rag gene-mediated resistance. Although the occurrence of these Rag virulent biotypes poses a serious threat to effective and sustainable management of soybean aphid, little is known about the current abundance of biotypes in North America. The objective of this research was to determine the distribution of Rag virulent soybean aphids in Wisconsin. Soybean aphids were collected from Wisconsin during the summers of 2012 and 2013, and assayed for Rag1, Rag2, and Rag1+2 virulence using no-choice tests in a greenhouse. One clone from Monroe County in 2012 reacted like biotype 4, three clones in different counties in 2013 responded like biotype 2, and eight others expressed varying degrees of Rag virulence. Rag virulence in 2013 was observed in aphids from 33% of the sampled sites and was accounted for by just 4.5% of sampled clones, although this is likely a conservative estimate. No-choice test results are discussed in light of current questions on the biology, ecology, and population genetics of soybean aphid. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Aggressive mimicry coexists with mutualism in an aphid

PubMed Central

Salazar, Adrián; Fürstenau, Benjamin; Quero, Carmen; Pérez-Hidalgo, Nicolás; Carazo, Pau; Font, Enrique; Martínez-Torres, David

2015-01-01

Understanding the evolutionary transition from interspecific exploitation to cooperation is a major challenge in evolutionary biology. Ant–aphid relationships represent an ideal system to this end because they encompass a coevolutionary continuum of interactions ranging from mutualism to antagonism. In this study, we report an unprecedented interaction along this continuum: aggressive mimicry in aphids. We show that two morphs clonally produced by the aphid Paracletus cimiciformis during its root-dwelling phase establish relationships with ants at opposite sides of the mutualism–antagonism continuum. Although one of these morphs exhibits the conventional trophobiotic (mutualistic) relationship with ants of the genus Tetramorium, aphids of the alternative morph are transported by the ants to their brood chamber and cared for as if they were true ant larvae. Gas chromatography-mass spectrometry analyses reveal that the innate cuticular hydrocarbon profile of the mimic morph resembles the profile of ant larvae more than that of the alternative, genetically identical nonmimic morph. Furthermore, we show that, once in the brood chamber, mimic aphids suck on ant larva hemolymph. These results not only add aphids to the limited list of arthropods known to biosynthesize the cuticular chemicals of their deceived hosts to exploit their resources but describe a remarkable case of plastic aggressive mimicry. The present work adds a previously unidentified dimension to the classical textbook paradigm of aphid–ant relationships by showcasing a complex system at the evolutionary interface between cooperation and exploitation. PMID:25583474

Genomic and Proteomic Analysis of Schizaphis graminum Reveals Cyclophilin Proteins Are Involved in the Transmission of Cereal Yellow Dwarf Virus

PubMed Central

Tamborindeguy, Cecilia; Bereman, Michael S.; DeBlasio, Stacy; Igwe, David; Smith, Dawn M.; White, Frank; MacCoss, Michael J.; Gray, Stewart M.; Cilia, Michelle

2013-01-01

Yellow dwarf viruses cause the most economically important virus diseases of cereal crops worldwide and are transmitted by aphid vectors. The identification of aphid genes and proteins mediating virus transmission is critical to develop agriculturally sustainable virus management practices and to understand viral strategies for circulative movement in all insect vectors. Two cyclophilin B proteins, S28 and S29, were identified previously in populations of Schizaphisgraminum that differed in their ability to transmit the RPV strain of Cereal yellow dwarf virus (CYDV-RPV). The presence of S29 was correlated with F2 genotypes that were efficient virus transmitters. The present study revealed the two proteins were isoforms, and a single amino acid change distinguished S28 and S29. The distribution of the two alleles was determined in 12 F2 genotypes segregating for CYDV-RPV transmission capacity and in 11 genetically independent, field-collected S . graminum biotypes. Transmission efficiency for CYDV-RPV was determined in all genotypes and biotypes. The S29 isoform was present in all genotypes or biotypes that efficiently transmit CYDV-RPV and more specifically in genotypes that efficiently transport virus across the hindgut. We confirmed a direct interaction between CYDV-RPV and both S28 and S29 using purified virus and bacterially expressed, his-tagged S28 and S29 proteins. Importantly, S29 failed to interact with a closely related virus that is transported across the aphid midgut. We tested for in vivo interactions using an aphid-virus co-immunoprecipitation strategy coupled with a bottom-up LC-MS/MS analysis using a Q Exactive mass spectrometer. This analysis enabled us to identify a third cyclophilin protein, cyclophilin A, interacting directly or in complex with purified CYDV-RPV. Taken together, these data provide evidence that both cyclophilin A and B interact with CYDV-RPV, and these interactions may be important but not sufficient to mediate virus transport

Long-term phenological trends, species accumulation rates, aphid traits and climate: five decades of change in migrating aphids.

PubMed

Bell, James R; Alderson, Lynda; Izera, Daniela; Kruger, Tracey; Parker, Sue; Pickup, Jon; Shortall, Chris R; Taylor, Mark S; Verrier, Paul; Harrington, Richard

2015-01-01

Aphids represent a significant challenge to food production. The Rothamsted Insect Survey (RIS) runs a network of 12·2-m suction-traps throughout the year to collect migrating aphids. In 2014, the RIS celebrated its 50th anniversary. This paper marks that achievement with an extensive spatiotemporal analysis and the provision of the first British annotated checklist of aphids since 1964. Our main aim was to elucidate mechanisms that advance aphid phenology under climate change and explain these using life-history traits. We then highlight emerging pests using accumulation patterns. Linear and nonlinear mixed-effect models estimated the average rate of change per annum and effects of climate on annual counts, first and last flights and length of flight season since 1965. Two climate drivers were used: the accumulated day degrees above 16 °C (ADD16) indicated the potential for migration during the aphid season; the North Atlantic Oscillation (NAO) signalled the severity of the winter before migration took place. All 55 species studied had earlier first flight trends at rate of β = -0·611 ± SE 0·015 days year(-1). Of these species, 49% had earlier last flights, but the average species effect appeared relatively stationary (β = -0·010 ± SE 0·022 days year(-1)). Most species (85%) showed increasing duration of their flight season (β = 0·336 ± SE 0·026 days year(-1)), even though only 54% increased their log annual count (β = 0·002 ± SE <0·001 year(-1)). The ADD16 and NAO were shown to drive patterns in aphid phenology in a spatiotemporal context. Early in the year when the first aphids were migrating, the effect of the winter NAO was highly significant. Further into the year, ADD16 was a strong predictor. Latitude had a near linear effect on first flights, whereas longitude produced a generally less-clear effect on all responses. Aphids that are anholocyclic (permanently parthenogenetic) or are monoecious (non

Aphid Species and Population Dynamics Associated with Strawberry.

PubMed

Bernardi, D; Araujo, E S; Zawadneak, M A C; Botton, M; Mogor, A F; Garcia, M S

2013-12-01

Aphids are among the major pests associated with strawberries in Southern Brasil. In this study, we identified the main species that occur in strawberry fields in the states of Paraná and Rio Grande do Sul, Brasil. We also compared the effectiveness of different sampling methods and studied the population dynamics of aphid species during two strawberry crop cycles in the municipality of Pinhais, state of Paraná, Brasil. Chaetosiphon fragaefolii (Cockerell) and Aphis forbesi Weed were the main species associated with strawberry. The method of hit plant and the Möericke trap showed equal effectiveness to capture wingless and winged insects. The peak population of aphids in the state of Paraná occurred from September to November. This information can help producers to implement strategies to monitor and control the major aphid species that occur in strawberry culture.

Social aggregation in pea aphids: experiment and random walk modeling.

PubMed

Nilsen, Christa; Paige, John; Warner, Olivia; Mayhew, Benjamin; Sutley, Ryan; Lam, Matthew; Bernoff, Andrew J; Topaz, Chad M

2013-01-01

From bird flocks to fish schools and ungulate herds to insect swarms, social biological aggregations are found across the natural world. An ongoing challenge in the mathematical modeling of aggregations is to strengthen the connection between models and biological data by quantifying the rules that individuals follow. We model aggregation of the pea aphid, Acyrthosiphon pisum. Specifically, we conduct experiments to track the motion of aphids walking in a featureless circular arena in order to deduce individual-level rules. We observe that each aphid transitions stochastically between a moving and a stationary state. Moving aphids follow a correlated random walk. The probabilities of motion state transitions, as well as the random walk parameters, depend strongly on distance to an aphid's nearest neighbor. For large nearest neighbor distances, when an aphid is essentially isolated, its motion is ballistic with aphids moving faster, turning less, and being less likely to stop. In contrast, for short nearest neighbor distances, aphids move more slowly, turn more, and are more likely to become stationary; this behavior constitutes an aggregation mechanism. From the experimental data, we estimate the state transition probabilities and correlated random walk parameters as a function of nearest neighbor distance. With the individual-level model established, we assess whether it reproduces the macroscopic patterns of movement at the group level. To do so, we consider three distributions, namely distance to nearest neighbor, angle to nearest neighbor, and percentage of population moving at any given time. For each of these three distributions, we compare our experimental data to the output of numerical simulations of our nearest neighbor model, and of a control model in which aphids do not interact socially. Our stochastic, social nearest neighbor model reproduces salient features of the experimental data that are not captured by the control.

Incidence and molecular diversity of poleroviruses infecting cucurbit crops and weed plants in Thailand.

PubMed

Cheewachaiwit, S; Warin, N; Phuangrat, B; Rukpratanporn, S; Gajanandana, O; Balatero, C H; Chatchawankanphanich, O

2017-07-01

Overall, 244 samples of cucurbit crops with yellowing symptoms and selected weed species, from 15 provinces in Thailand, were screened by RT-PCR using primers Polero-CP-F and Polero-CP-R. A total of 160 samples (~66%) were infected by poleroviruses. Analysis of a 1.4 kb region covering the 3' RNA-dependent RNA polymerase (RdRp) gene, the intergenic non-coding region (iNCR), and the coat protein (CP), showed that four poleroviruses, namely, cucurbit aphid-borne yellows virus (CABYV), luffa aphid-borne yellows virus (LABYV), melon aphid-borne yellows virus (MABYV) and suakwa aphid-borne yellows virus (SABYV) were associated with the yellowing symptoms in cucurbit crops. Further analyses indicated presence of putative recombinant viruses referred to as CABYV-R and SABYV-R. CABYV-R was derived from the recombination between MABYV and the common strain of CABYV (CABYV-C). SABYV-R was derived from the recombination of MABYV and SABYV.

Climate warming may increase aphids' dropping probabilities in response to high temperatures.

PubMed

Ma, Gang; Ma, Chun-Sen

2012-11-01

Dropping off is considered an anti-predator behavior for aphids since previous studies have shown that it reduces the risk of predation. However, little attention is paid to dropping behavior triggered by other external stresses such as daytime high temperatures which are predicted to become more frequent in the context of climate warming. Here we defined a new parameter, drop-off temperature (DOT), to describe the critical temperature at which an aphid drops off its host plant when the ambient temperature increases gradually and slowly. Detailed studies were conducted to reveal effects of short-term acclimation (temperature, exposure time at high-temperature and starvation) on DOT of an aphid species, Sitobion avenae. Our objectives were to test if the aphids dropped off host plant to avoid high temperatures and how short-term acclimation affected the aphids' dropping behavior in response to heat stress. We suggest that dropping is a behavioral thermoregulation to avoid heat stress, since aphids started to move before they dropped off and the dropped aphids were still able to control their muscles prior to knockdown. The adults starved for 12 h had higher DOT values than those that were unstarved or starved for 6 h, and there was a trade-off between behavioral thermoregulation and energy acquisition. Higher temperatures and longer exposure times at high temperatures significantly lowered the aphids' DOT, suggested that the aphids avoid heat stress by dropping when exposed to high temperatures. Climate warming may therefore increase the aphids' dropping probabilities and consequently affect the aphids' individual development and population growth. Copyright © 2012 Elsevier Ltd. All rights reserved.

Screening for sugarcane brown rust in first clonal stage of the Canal Point sugarcane breeding program

USDA-ARS?s Scientific Manuscript database

Sugarcane (Saccharum spp.) brown rust (caused by Puccinia melanocephala H. & P. Sydow) was first reported in the United States in 1978 and is still one of great challenges for sugarcane production. A better understanding of sugarcane genotypic variation in response to brown rust will help optimize b...

Field Performance of Transgenic Sugarcane Lines Resistant to Sugarcane Mosaic Virus

PubMed Central

Yao, Wei; Ruan, Miaohong; Qin, Lifang; Yang, Chuanyu; Chen, Rukai; Chen, Baoshan; Zhang, Muqing

2017-01-01

Sugarcane mosaic disease is mainly caused by the sugarcane mosaic virus (SCMV), which can significantly reduce stalk yield and sucrose content of sugarcane in the field. Coat protein mediated protection (CPMP) is an effective strategy to improve virus resistance. A 2-year field study was conducted to compare five independent transgenic sugarcane lines carrying the SCMV-CP gene (i.e., B2, B36, B38, B48, and B51) with the wild-type parental clone Badila (WT). Agronomic performance, resistance to SCMV infection, and transgene stability were evaluated and compared with the wild-type parental clone Badila (WT) at four experimental locations in China across two successive seasons, i.e., plant cane (PC) and 1st ratoon cane (1R). All transgenic lines derived from Badila had significantly greater tons of cane per hectare (TCH) and tons of sucrose per hectare (TSH) as well as lower SCMV disease incidence than those from Badila in the PC and 1R crops. The transgenic line B48 was highly resistant to SCMV with less than 3% incidence of infection. The recovery phenotype of transgenic line B36 was infected soon after virus inoculation, but the subsequent leaves showed no symptoms of infection. Most control plants developed symptoms that persisted and spread throughout the plant with more than 50% incidence. B48 recorded an average of 102.72 t/ha, which was 67.2% more than that for Badila. The expression of the transgene was stable over many generations with vegetative propagation. These results show that SCMV-resistant transgenic lines derived from Badila can provide resistant germplasm for sugarcane breeding and can also be used to study virus resistance mechanisms. This is the first report on the development and field performance of transgenic sugarcane plants that are resistant to SCMV infection in China. PMID:28228765

Field Performance of Transgenic Sugarcane Lines Resistant to Sugarcane Mosaic Virus.

PubMed

Yao, Wei; Ruan, Miaohong; Qin, Lifang; Yang, Chuanyu; Chen, Rukai; Chen, Baoshan; Zhang, Muqing

2017-01-01

Sugarcane mosaic disease is mainly caused by the sugarcane mosaic virus (SCMV), which can significantly reduce stalk yield and sucrose content of sugarcane in the field. Coat protein mediated protection (CPMP) is an effective strategy to improve virus resistance. A 2-year field study was conducted to compare five independent transgenic sugarcane lines carrying the SCMV-CP gene (i.e., B2, B36, B38, B48, and B51) with the wild-type parental clone Badila (WT). Agronomic performance, resistance to SCMV infection, and transgene stability were evaluated and compared with the wild-type parental clone Badila (WT) at four experimental locations in China across two successive seasons, i.e., plant cane (PC) and 1st ratoon cane (1R). All transgenic lines derived from Badila had significantly greater tons of cane per hectare (TCH) and tons of sucrose per hectare (TSH) as well as lower SCMV disease incidence than those from Badila in the PC and 1R crops. The transgenic line B48 was highly resistant to SCMV with less than 3% incidence of infection. The recovery phenotype of transgenic line B36 was infected soon after virus inoculation, but the subsequent leaves showed no symptoms of infection. Most control plants developed symptoms that persisted and spread throughout the plant with more than 50% incidence. B48 recorded an average of 102.72 t/ha, which was 67.2% more than that for Badila. The expression of the transgene was stable over many generations with vegetative propagation. These results show that SCMV-resistant transgenic lines derived from Badila can provide resistant germplasm for sugarcane breeding and can also be used to study virus resistance mechanisms. This is the first report on the development and field performance of transgenic sugarcane plants that are resistant to SCMV infection in China.

Development of a DNA microarray for species identification of quarantine aphids.

PubMed

Lee, Won Sun; Choi, Hwalran; Kang, Jinseok; Kim, Ji-Hoon; Lee, Si Hyeock; Lee, Seunghwan; Hwang, Seung Yong

2013-12-01

Aphid pests are being brought into Korea as a result of increased crop trading. Aphids exist on growth areas of plants, and thus plant growth is seriously affected by aphid pests. However, aphids are very small and have several sexual morphs and life stages, so it is difficult to identify species on the basis of morphological features. This problem was approached using DNA microarray technology. DNA targets of the cytochrome c oxidase subunit I gene were generated with a fluorescent dye-labelled primer and were hybridised onto a DNA microarray consisting of specific probes. After analysing the signal intensity of the specific probes, the unique patterns from the DNA microarray, consisting of 47 species-specific probes, were obtained to identify 23 aphid species. To confirm the accuracy of the developed DNA microarray, ten individual blind samples were used in blind trials, and the identifications were completely consistent with the sequencing data of all individual blind samples. A microarray has been developed to distinguish aphid species. DNA microarray technology provides a rapid, easy, cost-effective and accurate method for identifying aphid species for pest control management. © 2013 Society of Chemical Industry.

National Plant Diagnostic Network, Taxonomic training videos: Introduction to AphID

USDA-ARS?s Scientific Manuscript database

Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides visual instruction on the use of the expert system, AphID, for aphid examination and identification. The video demonstrates the use of different training modules that allow the user to gain familiarity wi...

Influences of pea morphology and interacting factors on pea aphid (Homoptera: Aphididae) reproduction.

PubMed

Buchman, N; Cuddington, K

2009-08-01

It has been claimed that plant architecture can alter aphid reproductive rates, but the mechanism driving this effect has not been identified. We studied interactions between plant architecture, aphid density, environmental conditions, and nutrient availability on the reproduction of pea aphids [Acyrthosiphon pisum (Harris)] using four near-isogenic peas (Pisum sativum L.) that differ in morphology. Manipulations of aphid density (1, 5, and 10 adults per plant) allowed us to examine any effects of plant morphology on crowding and consequently reproduction. Pea morphology per se did not alter pea aphid crowding, as measured by mean nearest neighbor distance, and there was no effect on reproduction. In addition, reproduction increased with increasing adult density, indicating positive density dependence. In a separate experiment, peas were fertilized to determine whether differences between nutrient availability of the four different morphologies might drive any observed differences in aphid reproduction. Although plant nitrogen content was altered by fertilization treatments, this did not have an impact on aphid reproduction. Greenhouse experiments, however, suggested that pea morphology can interact with environmental conditions to reduce aphid reproduction under some conditions. We conclude that plant morphology only influences aphid reproduction when environmental conditions are less than optimal.

Identification of Proteins Differentially Regulated in Response to Soybean Aphid Infestation of Soybean Near Isogenic Lines differing in Aphid Resistance

USDA-ARS?s Scientific Manuscript database

The soybean aphid, a plant sap sucking insect, has become an important soybean pest in the USA and infestation of soybean by this insect can lead to significant yield losses. The Rag2 gene of soybean, providing resistance to soybean aphid biotypes I (IL) and II (OH), was identified by researchers in...

Soybean Aphid Infestation Induces Changes in Fatty Acid Metabolism in Soybean

PubMed Central

Kanobe, Charles; McCarville, Michael T.; O’Neal, Matthew E.; Tylka, Gregory L.; MacIntosh, Gustavo C.

2015-01-01

The soybean aphid (Aphis glycines Matsumura) is one of the most important insect pests of soybeans in the North-central region of the US. It has been hypothesized that aphids avoid effective defenses by inhibition of jasmonate-regulated plant responses. Given the role fatty acids play in jasmonate-induced plant defenses, we analyzed the fatty acid profile of soybean leaves and seeds from aphid-infested plants. Aphid infestation reduced levels of polyunsaturated fatty acids in leaves with a concomitant increase in palmitic acid. In seeds, a reduction in polyunsaturated fatty acids was associated with an increase in stearic acid and oleic acid. Soybean plants challenged with the brown stem rot fungus or with soybean cyst nematodes did not present changes in fatty acid levels in leaves or seeds, indicating that the changes induced by aphids are not a general response to pests. One of the polyunsaturated fatty acids, linolenic acid, is the precursor of jasmonate; thus, these changes in fatty acid metabolism may be examples of “metabolic hijacking” by the aphid to avoid the induction of effective defenses. Based on the changes in fatty acid levels observed in seeds and leaves, we hypothesize that aphids potentially induce interference in the fatty acid desaturation pathway, likely reducing FAD2 and FAD6 activity that leads to a reduction in polyunsaturated fatty acids. Our data support the idea that aphids block jasmonate-dependent defenses by reduction of the hormone precursor. PMID:26684003

Aphids (Hemiptera, Aphididae) on ornamental plants in greenhouses in Bulgaria

PubMed Central

Yovkova, Mariya; Petrović-Obradović, Olivera; Tasheva-Terzieva, Elena; Pencheva, Aneliya

2013-01-01

Abstract Investigations on the species composition and host range of aphids on ornamental greenhouse plants in Bulgaria was conducted over a period of five years, from 2008 to 2012. Twenty greenhouses, growing ornamentals for landscaping, plant collections and other purposes were observed. They were located in the regions of Sofia, Plovdiv, Smolyan, Pavlikeni, Varna and Burgas. The total number of collected aphid samples was 279. Their composition included 33 aphid species and one subspecies from 13 genera and 5 subfamilies. Twenty-eight species were found to belong to subfamily Aphidinae. Almost 70 % of all recorded species were polyphagous. The most widespread aphid species was Myzus persicae, detected in 13 greenhouses all year round, followed by Aulacorthum solani (10 greenhouses) and Aphis gossypii (9 greenhouses). The widest host range was shown by Myzus persicae (43 hosts), Aulacorthum solani (32 hosts) and Aulacorthum circumflexum (23 hosts). The list of host plants includes 114 species from 95 genera and 58 families. The greatest variety of aphid species was detected on Hibiscus (9 species). Out of all aphid samples 12.9 % were collected on Hibiscus and 6.8 %, on Dendranthema. The greatest variety of aphid species was detected on Hibiscus (9 species). Periphyllus californiensis and Aphis (Aphis) fabae mordvilkoi are reported for the first time for Bulgaria. Furthermore, Aphis spiraecola has been found in new localities and has widened its host range in this country. PMID:24039530

Soybean defense responses to the soybean aphid.

PubMed

Li, Yan; Zou, Jijun; Li, Min; Bilgin, Damla D; Vodkin, Lila O; Hartman, Glen L; Clough, Steven J

2008-01-01

Transcript profiles in aphid (Aphis glycines)-resistant (cv. Dowling) and -susceptible (cv. Williams 82) soybean (Glycine max) cultivars using soybean cDNA microarrays were investigated. Large-scale soybean cDNA microarrays representing approx. 18 000 genes or c. 30% of the soybean genome were compared at 6 and 12 h post-application of aphids. In a separate experiment utilizing clip cages, expression of three defense-related genes were examined at 6, 12, 24, 48, and 72 h in both cultivars by quantitative real-time PCR. One hundred and forty genes showed specific responses for resistance; these included genes related to cell wall, defense, DNA/RNA, secondary metabolism, signaling and other processes. When an extended time period of sampling was investigated, earlier and greater induction of three defense-related genes was observed in the resistant cultivar; however, the induction declined after 24 or 48 h in the resistant cultivar but continued to increase in the susceptible cultivar after 24 h. Aphid-challenged resistant plants showed rapid differential gene expression patterns similar to the incompatible response induced by avirulent Pseudomonas syringae. Five genes were identified as differentially expressed between the two genotypes in the absence of aphids.

Bacteria may contribute to distant species recognition in ant-aphid mutualistic relationships.

PubMed

Fischer, Christophe Y; Detrain, Claire; Thonart, Philippe; Haubruge, Eric; Francis, Frédéric; Verheggen, François J; Lognay, Georges C

2017-04-01

Mutualistic interactions between ant and aphid species have been the subject of considerable historical and contemporary investigations, the primary benefits being cleaning and protection for the aphids and carbohydrate-rich honeydew for the ants. Questions remained, however, as to the volatile semiochemical factor influencing this relationship. A recent study highlighted the role of bacterial honeydew volatile compounds in ant attraction. Here, ant's ability to distantly discriminate 2 aphid species was investigated based on bacterial honeydew semiochemicals emissions using a two-way olfactometer. Both the mutualistic aphid Aphis fabae L. and the nonmyrmecophilous aphid Acyrthosiphon pisum Harris were found to be attractive for the ant Lasius niger L. The level of attraction was similar in both assays (control vs. one of the aphid species). However, when given a choice between these 2 aphid species, ants showed a significant preference for Aphis fabae. Honeydew volatiles, mostly from bacterial origins, are known to be a key element in ant attraction. Using the same olfactometry protocol, the relative attractiveness of volatiles emitted by honeydews collected from each aphid species and by bacteria isolated from each honeydew was investigated. Again, ants significantly preferred volatiles released by Aphis fabae honeydew and bacteria. This information suggests that microbial honeydew volatiles enable ants to distantly discriminate aphid species. These results strengthen the interest of studying the occurrence and potential impact of microorganisms in insect symbioses. © 2015 Institute of Zoology, Chinese Academy of Sciences.

Changes in the Russian Wheat Aphid (Hemiptera: Aphididae) Biotype Complex in South Africa.

PubMed

Jankielsohn, Astrid

2016-04-01

Russian wheat aphid Diuraphis noxia (Kurdjumov) has spread from its native area in central Asia to all the major wheat-producing countries in the world to become an international wheat pest. Because the Russian wheat aphid is a serious threat to the wheat industry in South Africa, it is important to investigate the key factors involved in the distribution of Russian wheat aphid biotypes and in the changes of the Russian wheat aphid biotype complex in South Africa. There are currently four known Russian wheat aphid biotypes occurring in South Africa. Russian wheat aphid samples were collected from 2011 to 2014 during the wheat-growing season in spring and summer and these samples were screened to determine the biotype status. RWASA1 occurred predominantly in the Western Cape, while RWASA2 and RWASA3 occurred predominantly in the Eastern Free State. Following the first record of RWASA4 in 2011, this biotype was restricted to the Eastern Free State. The surveys suggest that the Russian wheat aphid bioype complex was more diverse in the Eastern Free State than in the other wheat production areas. There was also a shift in Russian wheat aphid biotype composition over time. The Russian wheat aphid biotype complex is dynamic, influenced by environmental factors such as host plants, altitude, and climate, and it can change and diversify over time causing fluctuation in populations over sites and years. This dynamic nature of the Russian wheat aphid will continue to challenge the development of Russian wheat aphid-resistant wheat cultivars in South Africa, and the continued monitoring of the biotypic and genetic structure, to determine genetic relatedness and variation in different biotypes, of Russian wheat aphid populations is important for protecting wheat.

Effects of bacterial secondary symbionts on host plant use in pea aphids

PubMed Central

McLean, A. H. C.; van Asch, M.; Ferrari, J.; Godfray, H. C. J.

2011-01-01

Aphids possess several facultative bacterial symbionts that have important effects on their hosts' biology. These have been most closely studied in the pea aphid (Acyrthosiphon pisum), a species that feeds on multiple host plants. Whether secondary symbionts influence host plant utilization is unclear. We report the fitness consequences of introducing different strains of the symbiont Hamiltonella defensa into three aphid clones collected on Lathyrus pratensis that naturally lack symbionts, and of removing symbionts from 20 natural aphid–bacterial associations. Infection decreased fitness on Lathyrus but not on Vicia faba, a plant on which most pea aphids readily feed. This may explain the unusually low prevalence of symbionts in aphids collected on Lathyrus. There was no effect of presence of symbiont on performance of the aphids on the host plants of the clones from which the H. defensa strains were isolated. Removing the symbiont from natural aphid–bacterial associations led to an average approximate 20 per cent reduction in fecundity, both on the natural host plant and on V. faba, suggesting general rather than plant-species-specific effects of the symbiont. Throughout, we find significant genetic variation among aphid clones. The results provide no evidence that secondary symbionts have a major direct role in facilitating aphid utilization of particular host plant species. PMID:20843842

A cost of alarm pheromone production in cotton aphids, Aphis gossypii

NASA Astrophysics Data System (ADS)

Byers, John A.

2005-02-01

The sesquiterpene, (E)-β-farnesene, is used by many aphid species as an alarm pheromone to warn related individuals of predation. Disturbed cotton aphids, Aphis gossypii Glover, released (E)-β-farnesene into the air as detected by solid phase microextraction and gas chromatography mass spectrometry (GC MS). Solvent extracts of cotton aphids of various life stages and weights also were analyzed by GC MS for sums of ions 69 and 93, which discriminated (E)-β-farnesene from coeluting compounds. Aphids of all life stages and sizes reared on cotton plants in both an environmental chamber and glasshouse contained (E)-β-farnesene in amounts ranging from 0.1 to 1.5 ng per individual. The quantities of (E)-β-farnesene in aphids increased in relation to increasing body weight, and variation in individual weights explained about 82% of the variation in alarm pheromone. However, the concentrations (ng/mg fresh weight) declined exponentially with increasing body weight. These findings indicate that aphid nymphs try to compensate for their smaller size by producing relatively more pheromone per weight than adults but still cannot approach an evolutionary optimal load, as assumed in adults with the greatest total amounts. This suggests that young aphids need to balance costs of growth and maturation with costs of producing the alarm pheromone.

Overexpression of IRM1 Enhances Resistance to Aphids in Arabidopsis thaliana

PubMed Central

Chen, Xi; Zhang, Zhao; Visser, Richard G. F.; Broekgaarden, Colette; Vosman, Ben

2013-01-01

Aphids are insects that cause direct damage to crops by the removal of phloem sap, but more importantly they spread devastating viruses. Aphids use their sophisticated mouthpart (i.e. stylet) to feed from the phloem sieve elements of the host plant. To identify genes that affect host plant resistance to aphids, we previously screened an Arabidopsis thaliana activation tag mutant collection. In such mutants, tagged genes are overexpressed by a strong 35S enhancer adjacent to the natural promoter, resulting in a dominant gain-of-function phenotype. We previously identified several of these mutants on which the aphid Myzus persicae showed a reduced population development compared with wild type. In the present study we show that the gene responsible for the phenotype of one of the mutants is At5g65040 and named this gene Increased Resistance to Myzus persicae 1 (IRM1). Overexpression of the cloned IRM1 gene conferred a phenotype identical to that of the original mutant. Conversely, an IRM1 knockout mutant promoted aphid population development compared to the wild type. We performed Electrical Penetration Graph analysis to investigate how probing and feeding behaviour of aphids was affected on plants that either overexpressed IRM1 or contained a knockout mutation in this gene. The EPG results indicated that the aphids encounter resistance factors while reaching for the phloem on the overexpressing line. This resistance mechanism also affected other aphid species and is suggested to be of mechanical nature. Interestingly, genetic variation for IRM1 expression in response to aphid attack was observed. Upon aphid attack the expression of IRM1 was initially (after 6 hours) induced in ecotype Wassilewskija followed by suppression. In Columbia-0, IRM1 expression was already suppressed six hours after the start of the infestation. The resistance conferred by the overexpression of IRM1 in A. thaliana trades off with plant growth. PMID:23951039

Char from sugarcane bagasse

USDA-ARS?s Scientific Manuscript database

Unused sugarcane bagasse represents an underutilized resource in sugarcane growing regions of the world. This is a renewable resource that can be used in a thermochemical process to create chars, which could be incorporated back into agricultural activities. The practice is likely to improve soil ...

National Plant Diagnostic Network, Taxonomic training videos: Introduction to Aphids - Part 1

USDA-ARS?s Scientific Manuscript database

Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides visual instruction on important subject areas for aphid examination and identification. Aphid topics such as classification, morphology, plant disease transmission, and references are discussed. This dis...

AmeriFlux US-SuM Maui Sugarcane Middle

DOE Data Explorer

Anderson, Ray [USDA-Agricultural Research Service, United States Salinity Laboratory, Contaminant Fate and Transport Unit; Wang, Dong [USDA - Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Water Management Research Unit

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-SuM Maui Sugarcane Middle. Site Description - Continuous, irrigated, sugarcane cultivation for >100 years. Practice is to grow plant sugarcane for 2 years, drydown, burn leaves, harvest cane, and then till and replant very shortly after harvest. Site differs from Sugarcane Windy and Sugarcane Lee/sheltered in soil and meteorology.

AmeriFlux US-SuW Maui Sugarcane Windy

DOE Data Explorer

Anderson, Ray [USDA-Agricultural Research Service, United States Salinity Laboratory, Contaminant Fate and Transport Unit; Wang, Dong [USDA - Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Water Management Research Unit

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-SuW Maui Sugarcane Windy. Site Description - Continuous, irrigated, sugarcane cultivation for >100 years. Practice is to grow plant sugarcane for 2 years, drydown, burn leaves, harvest cane, and then till and replant very shortly after harvest. Site differs from Sugarcane Lee/Sheltered and Sugarcane Middle in soil type and site meteorology.

Do Aphids Alter Leaf Surface Temperature Patterns During Early Infestation?

PubMed Central

Cahon, Thomas; Caillon, Robin

2018-01-01

Arthropods at the surface of plants live in particular microclimatic conditions that can differ from atmospheric conditions. The temperature of plant leaves can deviate from air temperature, and leaf temperature influences the eco-physiology of small insects. The activity of insects feeding on leaf tissues, may, however, induce changes in leaf surface temperatures, but this effect was only rarely demonstrated. Using thermography analysis of leaf surfaces under controlled environmental conditions, we quantified the impact of presence of apple green aphids on the temperature distribution of apple leaves during early infestation. Aphids induced a slight change in leaf surface temperature patterns after only three days of infestation, mostly due to the effect of aphids on the maximal temperature that can be found at the leaf surface. Aphids may induce stomatal closure, leading to a lower transpiration rate. This effect was local since aphids modified the configuration of the temperature distribution over leaf surfaces. Aphids were positioned at temperatures near the maximal leaf surface temperatures, thus potentially experiencing the thermal changes. The feedback effect of feeding activity by insects on their host plant can be important and should be quantified to better predict the response of phytophagous insects to environmental changes. PMID:29538342

National Plant Diagnostic Network, Taxonomic training videos: Aphids under the microscope - overview

USDA-ARS?s Scientific Manuscript database

Training is a critical part of aphid (Hemiptera: Aphididae) identification. This training video provides provides an overview of general aphid morphology by using a compound microscope. The narrator discusses and highlights structures on the aphid that are important to make a species identification....

Release of Predators of the Balsam Woolly Aphid in North Carolina

Treesearch

Gene D. Amman; Charles F. Speers

1964-01-01

The balsam woolly aphid, Chermes piceae Ratz. (Homoptera: Chermidae), was accidentally introduced into North America from Europe about 1900 (Balch 1952). The aphid is now a serious pest of Fraser fir, Abies fraseri (Pursh)Poir., in the Southern Appalachians. Since its discovery in Northo-1957 (Speers 1958), the aphid has killed thousands of trees annually. Fraser fir...

Ecological effects of aphid abundance, genotypic variation, and contemporary evolution on plants.

PubMed

Turley, Nash E; Johnson, Marc T J

2015-07-01

Genetic variation and contemporary evolution within populations can shape the strength and nature of species interactions, but the relative importance of these forces compared to other ecological factors is unclear. We conducted a field experiment testing the effects of genotypic variation, abundance, and presence/absence of green peach aphids (Myzus persicae) on the growth, leaf nitrogen, and carbon of two plant species (Brassica napus and Solanum nigrum). Aphid genotype affected B. napus but not S. nigrum biomass explaining 20 and 7% of the total variation, respectively. Averaging across both plant species, the presence/absence of aphids had a 1.6× larger effect size (Cohen's d) than aphid genotype, and aphid abundance had the strongest negative effects on plant biomass explaining 29% of the total variation. On B. napus, aphid genotypes had different effects on leaf nitrogen depending on their abundance. Aphids did not influence leaf nitrogen in S. nigrum nor leaf carbon in either species. We conducted a second experiment in the field to test whether contemporary evolution could affect plant performance. Aphid populations evolved in as little as five generations, but the rate and direction of this evolution did not consistently vary between plant species. On one host species (B. napus), faster evolving populations had greater negative effects on host plant biomass, with aphid evolutionary rate explaining 23% of the variation in host plant biomass. Together, these results show that genetic variation and evolution in an insect herbivore can play important roles in shaping host plant ecology.

Aphid Transmission of the Ontario Isolate of Plum Pox Virus.

PubMed

Lowery, D Thomas; Vickers, Patricia M; Bittner, Lori A; Stobbs, Lorne W; Foottit, Robert G

2015-10-01

Utilization of timed virus acquisition access probes in studies of plum pox virus (PPV) transmission by aphids demonstrated that endemic species transmitted the virus readily from plum, Prunus domestica (L.) Batsch; peach, P. persica (L.); or dwarf flowering almond, P. glandulosa Thunberg., to peach seedlings. The green peach aphid, Myzus persicae (Sulzer), was shown to be the most efficient vector. Acquisition of virus by green peach aphids from infected peach leaves resulted in 18-28% infected peach seedlings, while aphids previously fed on infected leaves of plum transferred virus to 36% of peach seedlings. Although the spirea aphid, Aphis spiraecola (Patch), was a less efficient vector than M. persicae it is perhaps more important for the spread of PPV due to its greater abundance and occurrence earlier in the season when peach trees are thought to be more susceptible to infection. Virus transmission rates varied depending on the virus source and healthy test plant species. In contrast to many previous studies, aphid inoculation of the experimental host Nicotiana benthamiana Domin occurred at a low rate, never exceeding 4%. Acquisition of PPV by M. persicae from infected peach fruit was greatly reduced compared with acquisition from leaves. The results of this research indicate that the Ontario isolate of PPV-D is readily transmissible by aphids to peach and natural spread of the virus needs to be considered in future management or eradication programs. © Her Majesty in Right of Canada, as represented by the Minister of Agriculture and Agri-Food Canada. Published by Oxford University Press on behalf of Entomological Society of America.

Validation of a hairy roots system to study soybean-soybean aphid interactions

PubMed Central

Morriss, Stephanie C.; Studham, Matthew E.; Tylka, Gregory L.

2017-01-01

The soybean aphid (Aphis glycines) is one of the main insect pests of soybean (Glycine max) worldwide. Genomics approaches have provided important data on transcriptome changes, both in the insect and in the plant, in response to the plant-aphid interaction. However, the difficulties to transform soybean and to rear soybean aphid on artificial media have hindered our ability to systematically test the function of genes identified by those analyses as mediators of plant resistance to the insect. An efficient approach to produce transgenic soybean material is the production of transformed hairy roots using Agrobacterium rhizogenes; however, soybean aphids colonize leaves or stems and thus this approach has not been utilized. Here, we developed a hairy root system that allowed effective aphid feeding. We show that this system supports aphid performance similar to that observed in leaves. The use of hairy roots to study plant resistance is validated by experiments showing that roots generated from cotyledons of resistant lines carrying the Rag1 or Rag2 resistance genes are also resistant to aphid feeding, while related susceptible lines are not. Our results demonstrate that hairy roots are a good system to study soybean aphid-soybean interactions, providing a quick and effective method that could be used for functional analysis of the resistance response to this insect. PMID:28358854

New genus and species of the extinct aphid family Szelegiewicziidae and their implications for aphid evolution

NASA Astrophysics Data System (ADS)

Wegierek, Piotr; Żyła, Dagmara; Homan, Agnieszka; Cai, Chenyang; Huang, Diying

2017-12-01

Recently, we are witnessing an increased appreciation for the importance of the fossil record in phylogenetics and testing various evolutionary hypotheses. However, this approach brings many challenges, especially for such a complex group as aphids and requires a thorough morphological analysis of the extinct groups. The extinct aphid family Szelegiewicziidae is supposed to be one of the oviparous lineages in aphid evolution. New material from the rock fossil deposits of Shar Teg (Upper Jurassic of Mongolia), Baissa (Lower Cretaceous of Siberia-Russia), and Burmese amber (Upper Cretaceous of Myanmar) allowed us to undertake a more detailed examination of the morphological features and carry out an analysis of the taxonomical composition and evolution of the family. This led us to the conclusion that evolution of the body plan and wing structure was similar in different, often not closely related groups, probably as a result of convergence. Additionally, we present a description of a new genus and two species ( Tinaphis mongolica Żyła &Wegierek, sp. nov., and Feroorbis burmensis Wegierek & Huang, gen. et sp. nov.) that belong to this family.

New genus and species of the extinct aphid family Szelegiewicziidae and their implications for aphid evolution.

PubMed

Wegierek, Piotr; Żyła, Dagmara; Homan, Agnieszka; Cai, Chenyang; Huang, Diying

2017-10-24

Recently, we are witnessing an increased appreciation for the importance of the fossil record in phylogenetics and testing various evolutionary hypotheses. However, this approach brings many challenges, especially for such a complex group as aphids and requires a thorough morphological analysis of the extinct groups. The extinct aphid family Szelegiewicziidae is supposed to be one of the oviparous lineages in aphid evolution. New material from the rock fossil deposits of Shar Teg (Upper Jurassic of Mongolia), Baissa (Lower Cretaceous of Siberia-Russia), and Burmese amber (Upper Cretaceous of Myanmar) allowed us to undertake a more detailed examination of the morphological features and carry out an analysis of the taxonomical composition and evolution of the family. This led us to the conclusion that evolution of the body plan and wing structure was similar in different, often not closely related groups, probably as a result of convergence. Additionally, we present a description of a new genus and two species (Tinaphis mongolica Żyła &Wegierek, sp. nov., and Feroorbis burmensis Wegierek & Huang, gen. et sp. nov.) that belong to this family.

Potential Overwintering Locations of Soybean Aphid (Hemiptera: Aphididae) Colonizing Soybean in Ohio and Wisconsin.

PubMed

Crossley, Michael S; Hogg, David B

2015-04-01

Soybean aphids, Aphis glycines Matsumura, depend on long-distance, wind-aided dispersal to complete their life cycle. Despite our general understanding of soybean aphid biology, little is explicitly known about dispersal of soybean aphids between winter and summer hosts in North America. This study compared genotypic diversity of soybean aphids sampled from several overwintering locations in the Midwest and soybean fields in Ohio and Wisconsin to test the hypothesis that these overwintering locations are sources of the soybean colonists. In addition, air parcel trajectory analyses were used to demonstrate the potential for long-distance dispersal events to occur to or from these overwintering locations. Results suggest that soybean aphids from overwintering locations along the Illinois-Iowa border and northern Indiana-Ohio are potential colonists of soybean in Ohio and Wisconsin, but that Ohio is also colonized by soybean aphids from other unknown overwintering locations. Soybean aphids in Ohio and Wisconsin exhibit a small degree of population structure that is not associated with the locations of soybean fields in which they occur, but that may be related to specific overwintering environments, multiple introductions to North America, or spatial variation in aphid phenology. There may be a limited range of suitable habitat for soybean aphid overwintering, in which case management of soybean aphids may be more effective at their overwintering sites. Further research efforts should focus on discovering more overwintering locations of soybean aphid in North America, and the relative impact of short- and long-distance dispersal events on soybean aphid population dynamics. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Biological and genetic features of introduced aphid populations in agroecosystems.

PubMed

Figueroa, Christian C; Fuentes-Contreras, Eduardo; Molina-Montenegro, Marco A; Ramírez, Claudio C

2018-04-01

In agroecosystems, introduced aphids that reproduce by obligate parthenogenesis (OP) show strong biased representation of a few genotypes (superclones), whereas species with cyclical parthenogenesis (CP) exhibit the opposite trend with many unique genotypes. We analyzed the biological and genetic features of 23 different aphid species introduced in different geographic areas and climates, finding putative superclones in about 60% of them. We have examined the proximal causes for aphid establishment and spread after their introduction, and found that OP, host availability, and phenotypic plasticity are among the main variables underpinning the ability of aphids to succeed in new geographic areas, which may explain the high potential for invasion in this group of pest insects. Copyright © 2018 Elsevier Inc. All rights reserved.

Aphid Infestation Increases Fusarium langsethiae and T-2 and HT-2 Mycotoxins in Wheat

PubMed Central

Drakulic, Jassy; Ajigboye, Olubukola; Swarup, Ranjan; Bruce, Toby

2016-01-01

ABSTRACT Fusarium langsethiae is a fungal pathogen of cereal crops that is an increasing problem in northern Europe, but much of its epidemiology is poorly understood. The species produces the mycotoxins T-2 and HT-2, which are highly toxic. It was hypothesized that grain aphids, Sitobion avenae, may transmit F. langsethiae inoculum between wheat plants, and a series of transmission experiments and volatile chemical analyses was performed to test this. Manual translocation of aphids from inoculated to uninfected hosts resulted in pathogen DNA accumulation in hosts. However, the free movement of wingless aphids from infected to healthy plants did not. The addition of winged aphids reared on F. langsethiae-inoculated wheat seedlings to wheat plants also did not achieve successful pathogen transfer. While our data suggested that aphid transmission of the pathogen was not very efficient, we observed an increase in disease when aphids were present. After seedling inoculation, an increase in pathogen DNA accumulation in seedling leaves was observed upon treatment with aphids. Furthermore, the presence of aphids on wheat plants with F. langsethiae-inoculated ears not only led to a rise in the amount of F. langsethiae DNA in infected grain but also to an increase in the concentrations of T-2 and HT-2 toxins, with more than 3-fold higher toxin levels than diseased plants without aphids. This work highlights that aphids increase the susceptibility of wheat host plants to F. langsethiae and that aphid infestation is a risk factor for accumulating increased levels of T-2 and HT-2 in wheat products. IMPORTANCE Fusarium langsethiae is shown here to cause increased contamination levels of grain with toxins produced by fungus when aphids share the host plant. This effect has also recently been demonstrated with Fusarium graminearum, yet the two fungal species show stark differences in their effect on aphid populations. In both cases, aphids improve the ability of the pathogens to

Differential divergences of obligately insect-pathogenic Entomophthora species from fly and aphid hosts.

PubMed

Jensen, Annette Bruun; Eilenberg, Jørgen; López Lastra, Claudia

2009-11-01

Three DNA regions (ITS 1, LSU rRNA and GPD) of isolates from the insect-pathogenic fungus genus Entomophthora originating from different fly (Diptera) and aphid (Hemiptera) host taxa were sequenced. The results documented a large genetic diversity among the fly-pathogenic Entomophthora and only minor differences among aphid-pathogenic Entomophthora. The evolutionary time of divergence of the fly and the aphid host taxa included cannot account for this difference. The host-driven divergence of Entomophthora, therefore, has been much greater in flies than in aphids. Host-range differences or a recent host shift to aphid are possible explanations.

Enhanced Transgene Expression in Sugarcane by Co-Expression of Virus-Encoded RNA Silencing Suppressors

PubMed Central

Park, Jong-Won; Beyene, Getu; Buenrostro-Nava, Marco T.; Molina, Joe; Wang, Xiaofeng; Ciomperlik, Jessica J.; Manabayeva, Shuga A.; Alvarado, Veria Y.; Rathore, Keerti S.; Scholthof, Herman B.; Mirkov, T. Erik

2013-01-01

Post-transcriptional gene silencing is commonly observed in polyploid species and often poses a major limitation to plant improvement via biotechnology. Five plant viral suppressors of RNA silencing were evaluated for their ability to counteract gene silencing and enhance the expression of the Enhanced Yellow Fluorescent Protein (EYFP) or the β-glucuronidase (GUS) reporter gene in sugarcane, a major sugar and biomass producing polyploid. Functionality of these suppressors was first verified in Nicotiana benthamiana and onion epidermal cells, and later tested by transient expression in sugarcane young leaf segments and protoplasts. In young leaf segments co-expressing a suppressor, EYFP reached its maximum expression at 48–96 h post-DNA introduction and maintained its peak expression for a longer time compared with that in the absence of a suppressor. Among the five suppressors, Tomato bushy stunt virus-encoded P19 and Barley stripe mosaic virus-encoded γb were the most efficient. Co-expression with P19 and γb enhanced EYFP expression 4.6-fold and 3.6-fold in young leaf segments, and GUS activity 2.3-fold and 2.4-fold in protoplasts compared with those in the absence of a suppressor, respectively. In transgenic sugarcane, co-expression of GUS and P19 suppressor showed the highest accumulation of GUS levels with an average of 2.7-fold more than when GUS was expressed alone, with no detrimental phenotypic effects. The two established transient expression assays, based on young leaf segments and protoplasts, and confirmed by stable transgene expression, offer a rapid versatile system to verify the efficiency of RNA silencing suppressors that proved to be valuable in enhancing and stabilizing transgene expression in sugarcane. PMID:23799071

The significance of gut sucrase activity for osmoregulation in the pea aphid, Acyrthosiphon pisum.

PubMed

Karley, A J; Ashford, D A; Minto, L M; Pritchard, J; Douglas, A E

2005-12-01

The osmotic pressure of the body fluids of aphids is lower than in their diet of plant phloem sap. It is hypothesised that aphids reduce the osmotic pressure of ingested food by sucrase-mediated hydrolysis of dietary sucrose to glucose and fructose, and the polymerisation of glucose into oligosaccharides of low osmotic pressure per hexose unit. To test this hypothesis, the impact of the alpha-glucosidase inhibitor acarbose on the sugar relations and osmoregulation of aphids was explored. Acarbose inhibited sucrase activity in gut homogenates and the production of monosaccharides and oligosaccharides in the honeydew of live aphids. Acarbose caused an increase in the haemolymph osmotic pressure for aphids reared on a diet (containing 0.75 M sucrose) hyperosmotic to the haemolymph and not on the isoosmotic diet containing 0.2 M sucrose. It did not affect aphid feeding rate over 2 days, except at high concentrations on 0.75 M sucrose diet, and this may have been a secondary consequence of osmotic dysfunction. Acarbose-treated aphids died prematurely. With 5 microM dietary acarbose, mean survivorship on 0.2 M sucrose diet was 4.2 days, not significantly different from starved aphids, indicating that, although these aphids fed, they were deprived of utilisable carbon; and on 0.75 M sucrose diet, mean survivorship was just 2.8 days, probably as a consequence of osmotic failure. It is concluded that the aphid gut sucrase activity is essential for osmoregulation of aphids ingesting food hyperosmotic to their body fluids.

Registration of ‘Ho 02-113’ Sugarcane

USDA-ARS?s Scientific Manuscript database

‘Ho 02-113’ sugarcane was released by the USDA-ARS Sugarcane Research Unit working cooperatively with the Louisiana State University Agricultural Center, and the American Sugarcane League of the U.S.A. This high-fiber sugarcane variety was released for use as a biofuel feedstock to fill the rising i...

Inheritance patterns of secondary symbionts during sexual reproduction of pea aphid biotypes.

PubMed

Peccoud, Jean; Bonhomme, Joël; Mahéo, Frédérique; de la Huerta, Manon; Cosson, Olivier; Simon, Jean-Christophe

2014-06-01

Herbivorous insects frequently harbor bacterial symbionts that affect their ecology and evolution. Aphids host the obligatory endosymbiont Buchnera, which is required for reproduction, together with facultative symbionts whose frequencies vary across aphid populations. These maternally transmitted secondary symbionts have been particularly studied in the pea aphid, Acyrthosiphon pisum, which harbors at least 8 distinct bacterial species (not counting Buchnera) having environmentally dependent effects on host fitness. In particular, these symbiont species are associated with pea aphid populations feeding on specific plants. Although they are maternally inherited, these bacteria are occasionally transferred across insect lineages. One mechanism of such nonmaternal transfer is paternal transmission to the progeny during sexual reproduction. To date, transmission of secondary symbionts during sexual reproduction of aphids has been investigated in only a handful of aphid lineages and 3 symbiont species. To better characterize this process, we investigated inheritance patterns of 7 symbiont species during sexual reproduction of pea aphids through a crossing experiment involving 49 clones belonging to 9 host-specialized biotypes, and 117 crosses. Symbiont species in the progeny were detected with diagnostic qualitative PCR at the fundatrix stage hatching from eggs and in later parthenogenetic generations. We found no confirmed case of paternal transmission of symbionts to the progeny, and we observed that maternal transmission of a particular symbiont species (Serratia symbiotica) was quite inefficient. We discuss these observations in respect to the ecology of the pea aphid. © 2013 Institute of Zoology, Chinese Academy of Sciences.

The Effects of Aphid Traits on Parasitoid Host Use and Specialist Advantage

PubMed Central

Gagic, Vesna; Petrović-Obradović, Olivera; Fründ, Jochen; Kavallieratos, Nickolas G.; Athanassiou, Christos G.; Starý, Petr; Tomanović, Željko

2016-01-01

Specialization is a central concept in ecology and one of the fundamental properties of parasitoids. Highly specialized parasitoids tend to be more efficient in host-use compared to generalized parasitoids, presumably owing to the trade-off between host range and host-use efficiency. However, it remains unknown how parasitoid host specificity and host-use depends on host traits related to susceptibility to parasitoid attack. To address this question, we used data from a 13-year survey of interactions among 142 aphid and 75 parasitoid species in nine European countries. We found that only aphid traits related to local resource characteristics seem to influence the trade-off between host-range and efficiency: more specialized parasitoids had an apparent advantage (higher abundance on shared hosts) on aphids with sparse colonies, ant-attendance and without concealment, and this was more evident when host relatedness was included in calculation of parasitoid specificity. More traits influenced average assemblage specialization, which was highest in aphids that are monophagous, monoecious, large, highly mobile (easily drop from a plant), without myrmecophily, habitat specialists, inhabit non-agricultural habitats and have sparse colonies. Differences in aphid wax production did not influence parasitoid host specificity and host-use. Our study is the first step in identifying host traits important for aphid parasitoid host specificity and host-use and improves our understanding of bottom-up effects of aphid traits on aphid-parasitoid food web structure. PMID:27309729

Integrated disease management strategies in sugarcane cultivation

USDA-ARS?s Scientific Manuscript database

Sugarcane diseases cause severe losses to sugar production around the world. More than 100 bacterial, fungal, phytoplasma and viral diseases are present in sugarcane growing areas worldwide. Some diseases are present in most sugarcane growing regions while others are confined to specific countries. ...

A Genetic Survey of Pyrethroid Insecticide Resistance in Aphids in New Brunswick, Canada, with Particular Emphasis on Aphids as Vectors of Potato virus Y.

PubMed

MacKenzie, Tyler D B; Arju, Irin; Poirier, René; Singh, Mathuresh

2018-05-28

Aphids are viral vectors in potatoes, most importantly of Potato virus Y (PVY), and insecticides are frequently used to reduce viral spread during the crop season. Aphids collected from the potato belt of New Brunswick, Canada, in 2015 and 2016 were surveyed for known and novel mutations in the Na-channel (para) gene, coding for the target of synthetic pyrethroid insecticides. Specific genetic mutations known to confer resistance (kdr and skdr) were found in great abundance in Myzus persicae (Sulzer) (Hemiptera: Aphididae), which rose from 76% in 2015 to 96% in 2016. Aphids other than M. persicae showed lower frequency of resistance. In 2015, 3% of individuals contained the resistance mutation skdr, rising to 13% in 2016 (of 45 species). Several novel resistance mutations or mutations not before reported in aphids were identified in this gene target. One of these mutations, I936V, is known to confer pyrethroid resistance in another unrelated insect, and three others occur immediately adjacent and prompt similar chemical shifts in the primary protein structure, to previously characterized mutations associated with pyrethroid resistance. Most novel mutations were found in species other than M. persicae or others currently tracked individually by the provincial aphid monitoring program, which were determined by cytochrome C oxidase I (cox1) sequencing. Through our cox1 DNA barcoding survey, at least 45 species of aphids were discovered in NB potato fields in 2015 and 2016, many of which are known carriers of PVY.

Differential reactions of soybean isolines with combinations of aphid resistance genes Rag1, Rag2, and Rag3 to four soybean aphid biotypes

USDA-ARS?s Scientific Manuscript database

With the discovery of the soybean aphid (Aphis glycines Matsumura) as a devastating insect pest of soybean (Glycine max (L.) Merr.) in the United States, host resistance was recognized as an important management option. However, the identification of soybean aphid isolates exhibiting strong virulenc...

A Trio of Viral Proteins Tunes Aphid-Plant Interactions in Arabidopsis thaliana

PubMed Central

Du, Zhiyou; Murphy, Alex M.; Anggoro, Damar Tri; Tungadi, Trisna; Luang-In, Vijitra; Lewsey, Mathew G.; Rossiter, John T.; Powell, Glen; Smith, Alison G.; Carr, John P.

2013-01-01

Background Virus-induced deterrence to aphid feeding is believed to promote plant virus transmission by encouraging migration of virus-bearing insects away from infected plants. We investigated the effects of infection by an aphid-transmitted virus, cucumber mosaic virus (CMV), on the interaction of Arabidopsis thaliana, one of the natural hosts for CMV, with Myzus persicae (common names: ‘peach-potato aphid’, ‘green peach aphid’). Methodology/Principal Findings Infection of Arabidopsis (ecotype Col-0) with CMV strain Fny (Fny-CMV) induced biosynthesis of the aphid feeding-deterrent 4-methoxy-indol-3-yl-methylglucosinolate (4MI3M). 4MI3M inhibited phloem ingestion by aphids and consequently discouraged aphid settling. The CMV 2b protein is a suppressor of antiviral RNA silencing, which has previously been implicated in altering plant-aphid interactions. Its presence in infected hosts enhances the accumulation of CMV and the other four viral proteins. Another viral gene product, the 2a protein (an RNA-dependent RNA polymerase), triggers defensive signaling, leading to increased 4MI3M accumulation. The 2b protein can inhibit ARGONAUTE1 (AGO1), a host factor that both positively-regulates 4MI3M biosynthesis and negatively-regulates accumulation of substance(s) toxic to aphids. However, the 1a replicase protein moderated 2b-mediated inhibition of AGO1, ensuring that aphids were deterred from feeding but not poisoned. The LS strain of CMV did not induce feeding deterrence in Arabidopsis ecotype Col-0. Conclusions/Significance Inhibition of AGO1 by the 2b protein could act as a booby trap since this will trigger antibiosis against aphids. However, for Fny-CMV the interplay of three viral proteins (1a, 2a and 2b) appears to balance the need of the virus to inhibit antiviral silencing, while inducing a mild resistance (antixenosis) that is thought to promote transmission. The strain-specific effects of CMV on Arabidopsis-aphid interactions, and differences between

Host Plants Indirectly Influence Plant Virus Transmission by Altering Gut Cysteine Protease Activity of Aphid Vectors*

PubMed Central

Pinheiro, Patricia V.; Ghanim, Murad; Rebelo, Ana Rita; Santos, Rogerio S.; Orsburn, Benjamin C.; Gray, Stewart

2017-01-01

The green peach aphid, Myzus persicae, is a vector of the Potato leafroll virus (PLRV, Luteoviridae), transmitted exclusively by aphids in a circulative manner. PLRV transmission efficiency was significantly reduced when a clonal lineage of M. persicae was reared on turnip as compared with the weed physalis, and this was a transient effect caused by a host-switch response. A trend of higher PLRV titer in physalis-reared aphids as compared with turnip-reared aphids was observed at 24 h and 72 h after virus acquisition. The major difference in the proteomes of these aphids was the up-regulation of predicted lysosomal enzymes, in particular the cysteine protease cathepsin B (cathB), in aphids reared on turnip. The aphid midgut is the site of PLRV acquisition, and cathB and PLRV localization were starkly different in midguts of the aphids reared on the two host plants. In viruliferous aphids that were reared on turnip, there was near complete colocalization of cathB and PLRV at the cell membranes, which was not observed in physalis-reared aphids. Chemical inhibition of cathB restored the ability of aphids reared on turnip to transmit PLRV in a dose-dependent manner, showing that the increased activity of cathB and other cysteine proteases at the cell membrane indirectly decreased virus transmission by aphids. Understanding how the host plant influences virus transmission by aphids is critical for growers to manage the spread of virus among field crops. PMID:27932519

[An example of research on biological control: Entomophthora fungi pathogenic for aphids].

PubMed

Latgé, J P; Remaudière, G; Papierok, B

1978-01-01

The results obtained in 15 years of research on the Entomophthorales pathogen of aphids showed the importance of the action of these fungi in the regulation of natural aphid populations and their possible use in agriculture as a biological control agent. Recent ecological studies on natural populations of aphids established the seasonal variation of the different fungal species and the diverse degrees of specificity between the species or groups of species of aphid and the various species of Entomophthora. The study of populations dynamics of an aphid species on a cultivated plant permitted the determination of the way a certain number of biotic and abiotic factors, such as temperature, humidity, thresholds of the insect population and of the infecting fungus lead to an epizootic development. If the air propagation of the disease by conidia is understood for a long time, the role of the soil as a reservoir for the infecting fungus has been demonstrated recently. Under favourable climatic conditions, the use of industrially produced resistant resting spores would allow the regulation of aphid populations in nature.

Sugarcane Elongin C is involved in infection by sugarcane mosaic disease pathogens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhai, Yushan; Deng, Yuqing; Cheng, Guangyuan

Sugarcane (Saccharum sp. hybrid) provides the main source of sugar for humans. Sugarcane mosaic disease (SMD) is a major threat to sugarcane production. Currently, control of SMD is mainly dependent on breeding resistant cultivars through hybridization, which is time-consuming. Understanding the mechanism of viral infection may facilitate novel strategies to breed cultivars resistant to SMD and to control the disease. In this study, a wide interaction was detected between the viral VPg protein and host proteins. Several genes were screened from sugarcane cDNA library that could interact with Sugarcane streak mosaic virus VPg, including SceIF4E1 and ScELC. ScELC was predictedmore » to be a cytoplasmic protein, but subcellular localization analysis showed it was distributed both in cytoplasmic and nuclear, and interactions were also detected between ScELC and VPg of SCMV or SrMV that reveal ScELC was widely used in the SMD pathogen infection process. ScELC and VPgs interacted in the nucleus, and may function to enhance the viral transcription rate. ScELC also interacted with SceIF4E2 both in the cytoplasm and nucleus, but not with SceIF4E1 and SceIF4E3. These results suggest that ScELC may be essential for the function of SceIF4E2, an isomer of eIF4E. - Highlights: • We cloned ScELC, SceIF4E1, SceIF4E2 and SceIF4E3 from sugarcane accession Badila. • We examined interactions among VPg, ScELC, SceIF4E1, SceIF4E2 and SceIF4E3. • We proofed that ScELC interacted with VPgs of SCMV, SrMV and SCSMV. • We proofed that ScELC interacted with SceIF4E2 but not SceIF4E1 or SceIF4E3.« less

Tracking the global dispersal of a cosmopolitan insect pest, the peach potato aphid.

PubMed

Margaritopoulos, John T; Kasprowicz, Louise; Malloch, Gaynor L; Fenton, Brian

2009-05-11

Global commerce and human transportation are responsible for the range expansion of various insect pests such as the plant sucking aphids. High resolution DNA markers provide the opportunity to examine the genetic structure of aphid populations, identify aphid genotypes and infer their evolutionary history and routes of expansion which is of value in developing management strategies. One of the most widespread aphid species is the peach-potato aphid Myzus persicae, which is considered as a serious pest on various crops in many parts of the world. The present study examined the genetic variation of this aphid at a world scale and then related this to distribution patterns. In particular, 197 aphid parthenogenetic lineages from around the world were analysed with six microsatellite loci. Bayesian clustering and admixture analysis split the aphid genotypes into three genetic clusters: European M. persicae persicae, New Zealand M. persicae persicae and Global M. persicae nicotianae. This partition was supported by FST and genetic distance analyses. The results showed two further points, a possible connection between genotypes found in the UK and New Zealand and globalization of nicotianae associated with colonisation of regions where tobacco is not cultivated. In addition, we report the presence of geographically widespread clones and for the first time the presence of a nicotianae genotype in the Old and New World. Lastly, heterozygote deficiency was detected in some sexual and asexual populations. The study revealed important genetic variation among the aphid populations we examined and this was partitioned according to region and host-plant. Clonal selection and gene flow between sexual and asexual lineages are important factors shaping the genetic structure of the aphid populations. In addition, the results reflected the globalization of two subspecies of M. persicae with successful clones being spread at various scales throughout the world. A subspecies appears to

Cybertaxonomy to accomplish big things in aphid systematics.

PubMed

Favret, Colin

2014-06-01

Biodiversity sciences have progressed at such a pace that the taxonomic community has been unable to grow concomitantly to keep up with the influx of biological data. This "taxonomic impediment" has led some to suggest that taxonomy is no longer pertinent and to the development of methodologies that circumvent the taxonomic process. This article does not seek to argue for the importance of taxonomy but rather is a call to the aphid taxonomy community to rise to the challenge by dramatically increasing the volume and comprehensiveness of its output without sacrificing quality. Recent informatics technology allows us to mobilize the 2 most important aphid taxonomy resources: experts and specimens, both distributed globally. "Cyberspecimens," museum specimens digitally rendered at a resolution sufficient for remote identification, and open "cybertaxonomic" tools will allow the international aphid taxonomic community to carry out large, ambitious, projects. The global aphid cybertaxonomy proposed here will serve not only the ends of research aphidologists, but also provide a model for other taxonomic communities to adapt and adopt as we confront both the taxonomic impediment and the taxonomic naysayers. © 2013 Institute of Zoology, Chinese Academy of Sciences.

Kenaf and cowpea as sugarcane cover crops

USDA-ARS?s Scientific Manuscript database

The use of cover crops during the fallow period prior to planting sugarcane has the potential to influence not only the following sugarcane crop, but the economics of the production system as a whole. Typically, a Louisiana sugarcane field is replanted every four years due to declining yields, and,...

Evidence for compensatory photosynthetic and yield response of soybeans to aphid herbivory

DOE PAGES

Kucharik, Christopher J.; Mork, Amelia C.; Meehan, Timothy D.; ...

2016-04-13

The soybean aphid, Aphis glycines Matsumura, an exotic species in North America that has been detected in 21 U.S. states and Canada, is a major pest for soybean that can reduce maximum photosynthetic capacity and yields. Our existing knowledge is based on relatively few studies that do not span a wide variety of environmental conditions, and often focus on relatively high and damaging population pressure. We examined the effects of varied populations and duration of soybean aphids on soybean photosynthetic rates and yield in two experiments. In a 2011 field study, we found that plants with low cumulative aphid daysmore » (CAD, less than 2,300) had higher yields than plants not experiencing significant aphid pressure, suggesting a compensatory growth response to low aphid pressure. This response did not hold at higher CAD, and yields declined. In a 2013 controlled-environment greenhouse study, soybean plants were well-watered and fertilized with nitrogen (N), and aphid populations were manipulated to reach moderate to high levels (8,000–50,000 CAD). Plants tolerated these population levels when aphids were introduced during the vegetative or reproductive phenological stages of the plant, showing no significant reduction in yield. Leaf N concentration and CAD were positively and significantly correlated with increasing ambient photosynthetic rates. Our findings suggest that, given the right environmental conditions, modern soybean plants can withstand higher aphid pressure than previously assumed. Moreover, soybean plants also responded positively through a compensatory photosynthetic effect to moderate population pressure, contributing to stable or increased yield.« less

Particle film affects black pecan aphid (Homoptera: Aphididae) on pecan.

PubMed

Cottrell, Ted E; Wood, Bruce W; Reilly, Charles C

2002-08-01

Three species of aphids attack pecan foliage, Carya illinoensis (Wang.) K. Koch, and cause economic damage. We tested a kaolin-based particle film against one of these aphid species, black pecan aphid, Melanocallis caryaefoliae (Davis). Effect of particle film on host selection, adult mortality, and production of nymphs by M. caryaefoliae was tested on seedling pecans in the laboratory. Fewer M. caryaefoliae adults selected treated foliage compared with untreated foliage. A higher percentage of adults that did select treated foliage were recovered from upper leaf surfaces compared with the percentage of adults recovered from upper leaf surfaces of untreated leaves. Observations with a microscope revealed an accumulation of particle film on aphid body parts, especially on tarsi, and strongly suggests that aphid mobility was restricted. Adult mortality was higher on treated foliage and led to an overall decrease in production of nymphs on those seedlings. In addition, we measured spectral properties of treated seedling pecan foliage. Light reflectance by treated foliage was increased and absorptance decreased compared with control foliage whereas transmittance of light through control and particle film-treated leaves was similar. We did not detect any phytotoxic effect on pecan due to application of particle film.

Variable isotopic compositions of host plant populations preclude assessment of aphid overwintering sites

USDA-ARS?s Scientific Manuscript database

Soybean aphid (Aphis glycines Matsumura) is a pest of soybean in the northern Midwest whose migratory patterns have been difficult to quantify. Improved knowledge of soybean aphid overwintering sites could facilitate the development of control efforts with exponential impacts on aphid densities on a...

Host Plants Indirectly Influence Plant Virus Transmission by Altering Gut Cysteine Protease Activity of Aphid Vectors.

PubMed

Pinheiro, Patricia V; Ghanim, Murad; Alexander, Mariko; Rebelo, Ana Rita; Santos, Rogerio S; Orsburn, Benjamin C; Gray, Stewart; Cilia, Michelle

2017-04-01

The green peach aphid, Myzus persicae , is a vector of the Potato leafroll virus (PLRV, Luteoviridae), transmitted exclusively by aphids in a circulative manner. PLRV transmission efficiency was significantly reduced when a clonal lineage of M. persicae was reared on turnip as compared with the weed physalis, and this was a transient effect caused by a host-switch response. A trend of higher PLRV titer in physalis-reared aphids as compared with turnip-reared aphids was observed at 24 h and 72 h after virus acquisition. The major difference in the proteomes of these aphids was the up-regulation of predicted lysosomal enzymes, in particular the cysteine protease cathepsin B (cathB), in aphids reared on turnip. The aphid midgut is the site of PLRV acquisition, and cathB and PLRV localization were starkly different in midguts of the aphids reared on the two host plants. In viruliferous aphids that were reared on turnip, there was near complete colocalization of cathB and PLRV at the cell membranes, which was not observed in physalis-reared aphids. Chemical inhibition of cathB restored the ability of aphids reared on turnip to transmit PLRV in a dose-dependent manner, showing that the increased activity of cathB and other cysteine proteases at the cell membrane indirectly decreased virus transmission by aphids. Understanding how the host plant influences virus transmission by aphids is critical for growers to manage the spread of virus among field crops. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Salinity Improves Performance and Alters Distribution of Soybean Aphids.

PubMed

Eichele-Nelson, Jaclyn; DeSutter, Thomas; Wick, Abbey F; Harmon, Erin L; Harmon, Jason P

2018-05-24

We know numerous abiotic factors strongly influence crop plants. Yet we often know much less about abiotic effects on closely interacting organisms including herbivorous insects. This lack of a whole-system perspective may lead to underestimating the threats from changing factors. High soil salinity is a specific example that we know threatens crop plants in many places, but we need to know much more about how other organisms are also affected. We investigated how salinity affects the soybean aphid (SBA; Aphis glycines Matsumura; Hemiptera: Aphididae) on soybean plants (Glycine max [L.] Merr.; Fabales: Fabaceae) grown across a range of saline conditions. We performed four complementary greenhouse experiments to understand different aspects of how salinity might affect SBA. We found that as salinity increased both population size and fecundity of SBA increased across electrical conductivity values ranging from 0.84 to 8.07 dS m-1. Tracking individual aphids we also found they lived longer and produced more offspring in high saline conditions compared to the control. Moreover, we found that salinity influenced aphid distribution such that when given the chance aphids accumulated more on high-salinity plants. These results suggest that SBA could become a larger problem in areas with higher salinity and that those aphids may exacerbate the negative effects of salinity for soybean production.

Prevalence of entomophthoralean fungi (Entomophthoromycota) of aphids in relation to developmental stages.

PubMed

Manfrino, Romina G; Gutierrez, Alejandra C; Rueda Páramo, Manuel E; Salto, César E; López Lastra, Claudia C

2016-08-01

Transmission of fungal pathogens of aphids may be affected by the host developmental stage. Brassica and Lactuca sativa L. crops were sampled in Santa Fe, Argentina, to determine the prevalence of fungal-diseased aphids and investigate the differences between developmental stages of aphids. The fungal pathogens identified were Zoophthora radicans (Bref.) A. Batko, Pandora neoaphidis (Remaud. & Hennebert) Humber and Entomophthora planchoniana Cornu. Their prevalence on each crop was calculated. The numbers of infected aphids were significantly different between the different developmental stages on all crops except B. oleracea var. botrytis L. The entomophthoralean fungi identified are important mortality factors of aphids on horticultural crops in Santa Fe. The numbers of infected nymphs and adults were significantly different, nymphs being the most affected developmental stage. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Transgenic sugarcane overexpressing CaneCPI-1 negatively affects the growth and development of the sugarcane weevil Sphenophorus levis.

PubMed

Schneider, Vanessa Karine; Soares-Costa, Andrea; Chakravarthi, Mohan; Ribeiro, Carolina; Chabregas, Sabrina Moutinho; Falco, Maria Cristina; Henrique-Silva, Flavio

2017-01-01

Transgenic sugarcane expressing CaneCPI-1 exhibits resistance to Sphenophorus levis larvae. Transgenic plants have widely been used to improve resistance against insect attack. Sugarcane is an economically important crop; however, great losses are caused by insect attack. Sphenophorus levis is a sugarcane weevil that digs tunnels in the stem base, leading to the destruction of the crop. This insect is controlled inefficiently by chemical insecticides. Transgenic plants expressing peptidase inhibitors represent an important strategy for impairing insect growth and development. Knowledge of the major peptidase group present in the insect gut is critical when choosing the most effective inhibitor. S. levis larvae use cysteine peptidases as their major digestive enzymes, primarily cathepsin L-like activity. In this study, we developed transgenic sugarcane plants that overexpress sugarcane cysteine peptidase inhibitor 1 (CaneCPI-1) and assessed their potential through feeding bioassays with S. levis larvae. Cystatin overexpression in the transgenic plants was evaluated using semi-quantitative RT-PCR, RT-qPCR, and immunoblot assays. A 50% reduction of the average weight was observed in larvae that fed on transgenic plants in comparison to larvae that fed on non-transgenic plants. In addition, transgenic sugarcane exhibited less damage caused by larval attack than the controls. Our results suggest that the overexpression of CaneCPI-1 in sugarcane is a promising strategy for improving resistance against this insect.

Sugarcane Diseases: Futuristic Management Strategies

USDA-ARS?s Scientific Manuscript database

Sugarcane pathology and disease control practices are changing due to social, economic and technological events. Sugarcane is becoming more important economically because of the increasing price and demand for sugar and its use for bio-energy. These pressures make the control of diseases more import...

Blackmargined aphid (Monellia caryella (Fitch); Hemiptera: Aphididae) honeydew production in pecan (Carya illinoinesis (Koch)) and implications for managing the pecan aphid complex in Texas

USDA-ARS?s Scientific Manuscript database

Field studies of the blackmargined aphid, Monellia caryella (Fitch), were conducted on three cultivars, “Cheyenne,” “Kiowa,” and “Pawnee,” of pecan, Carya illinoinisis (Wang) K. Koch. Aphid and natural enemy (lacewings, ladybird beetles, and spiders) densities were determined twice weekly by direct...

Orally Delivered Scorpion Antimicrobial Peptides Exhibit Activity against Pea Aphid (Acyrthosiphon pisum) and Its Bacterial Symbionts.

PubMed

Luna-Ramirez, Karen; Skaljac, Marisa; Grotmann, Jens; Kirfel, Phillipp; Vilcinskas, Andreas

2017-08-24

Aphids are severe agricultural pests that damage crops by feeding on phloem sap and vectoring plant pathogens. Chemical insecticides provide an important aphid control strategy, but alternative and sustainable control measures are required to avoid rapidly emerging resistance, environmental contamination, and the risk to humans and beneficial organisms. Aphids are dependent on bacterial symbionts, which enable them to survive on phloem sap lacking essential nutrients, as well as conferring environmental stress tolerance and resistance to parasites. The evolution of aphids has been accompanied by the loss of many immunity-related genes, such as those encoding antibacterial peptides, which are prevalent in other insects, probably because any harm to the bacterial symbionts would inevitably affect the aphids themselves. This suggests that antimicrobial peptides (AMPs) could replace or at least complement conventional insecticides for aphid control. We fed the pea aphids ( Acyrthosiphon pisum ) with AMPs from the venom glands of scorpions. The AMPs reduced aphid survival, delayed their reproduction, displayed in vitro activity against aphid bacterial symbionts, and reduced the number of symbionts in vivo. Remarkably, we found that some of the scorpion AMPs compromised the aphid bacteriome, a specialized organ that harbours bacterial symbionts. Our data suggest that scorpion AMPs holds the potential to be developed as bio-insecticides, and are promising candidates for the engineering of aphid-resistant crops.

Orally Delivered Scorpion Antimicrobial Peptides Exhibit Activity against Pea Aphid (Acyrthosiphon pisum) and Its Bacterial Symbionts

PubMed Central

Luna-Ramirez, Karen; Skaljac, Marisa; Grotmann, Jens; Kirfel, Phillipp; Vilcinskas, Andreas

2017-01-01

Aphids are severe agricultural pests that damage crops by feeding on phloem sap and vectoring plant pathogens. Chemical insecticides provide an important aphid control strategy, but alternative and sustainable control measures are required to avoid rapidly emerging resistance, environmental contamination, and the risk to humans and beneficial organisms. Aphids are dependent on bacterial symbionts, which enable them to survive on phloem sap lacking essential nutrients, as well as conferring environmental stress tolerance and resistance to parasites. The evolution of aphids has been accompanied by the loss of many immunity-related genes, such as those encoding antibacterial peptides, which are prevalent in other insects, probably because any harm to the bacterial symbionts would inevitably affect the aphids themselves. This suggests that antimicrobial peptides (AMPs) could replace or at least complement conventional insecticides for aphid control. We fed the pea aphids (Acyrthosiphon pisum) with AMPs from the venom glands of scorpions. The AMPs reduced aphid survival, delayed their reproduction, displayed in vitro activity against aphid bacterial symbionts, and reduced the number of symbionts in vivo. Remarkably, we found that some of the scorpion AMPs compromised the aphid bacteriome, a specialized organ that harbours bacterial symbionts. Our data suggest that scorpion AMPs holds the potential to be developed as bio-insecticides, and are promising candidates for the engineering of aphid-resistant crops. PMID:28837113

The Green Lacewing, Chrysoperla carnea: Preference between Lettuce Aphids, Nasonovia ribisnigri, and Western Flower Thrips, Frankliniella occidentalis

PubMed Central

Shrestha, Govinda; Enkegaard, Annie

2013-01-01

This study investigated the prey preference of 3rd instar green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), between western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), and lettuce aphids, Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) in laboratory experiments at 25 ± 1° C and 70 ± 5% RH with five prey ratios (10 aphids:80 thrips, 25 aphids:65 thrips, 45 aphids:45 thrips, 65 aphids:25 thrips, and 80 aphids:10 thrips). Third instar C. carnea larvae readily preyed upon both thrips and aphids, with thrips mortality varying between 40 and 90%, and aphid mortality between 52 and 98%. Chrysoperla carnea had a significant preference for N. ribisnigri at two ratios (10 aphids:80 thrips, 65 aphids:25 thrips), but no preference for either prey at the other ratios. There was no significant linear relationship between preference index and prey ratio, but a significant intercept of the linear regression indicated an overall preference of C. carnea for aphids with a value of 0.651 ± 0.054. The possible implications of these findings for control of N. ribisnigri and F. occidentalis by C. carnea are discussed. PMID:24205864

The green lacewing, Chrysoperla carnea: preference between lettuce aphids, Nasonovia ribisnigri, and Western flower thrips, Frankliniella occidentalis.

PubMed

Shrestha, Govinda; Enkegaard, Annie

2013-01-01

This study investigated the prey preference of 3(rd) instar green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), between western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), and lettuce aphids, Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae) in laboratory experiments at 25 ± 1° C and 70 ± 5% RH with five prey ratios (10 aphids:80 thrips, 25 aphids:65 thrips, 45 aphids:45 thrips, 65 aphids:25 thrips, and 80 aphids:10 thrips). Third instar C. carnea larvae readily preyed upon both thrips and aphids, with thrips mortality varying between 40 and 90%, and aphid mortality between 52 and 98%. Chrysoperla carnea had a significant preference for N. ribisnigri at two ratios (10 aphids:80 thrips, 65 aphids:25 thrips), but no preference for either prey at the other ratios. There was no significant linear relationship between preference index and prey ratio, but a significant intercept of the linear regression indicated an overall preference of C. carnea for aphids with a value of 0.651 ± 0.054. The possible implications of these findings for control of N. ribisnigri and F. occidentalis by C. carnea are discussed.

Variable Isotopic Compositions of Host Plant Populations Preclude Assessment of Aphid Overwintering Sites

PubMed Central

Voegtlin, David J.; Hamilton, Krista L.; Hogg, David B.

2017-01-01

Soybean aphid (Aphis glycines Matsumura) is a pest of soybean in the northern Midwest whose migratory patterns have been difficult to quantify. Improved knowledge of soybean aphid overwintering sites could facilitate the development of control efforts with exponential impacts on aphid densities on a regional scale. In this preliminary study, we explored the utility of variation in stable isotopes of carbon and nitrogen to distinguish soybean aphid overwintering origins. We compared variation in bulk 13C and 15N content in buckthorn (Rhamnus cathartica L.) and soybean aphids in Wisconsin, among known overwintering locations in the northern Midwest. Specifically, we looked for associations between buckthorn and environmental variables that could aid in identifying overwintering habitats. We detected significant evidence of correlation between the bulk 13C and 15N signals of soybean aphids and buckthorn, despite high variability in stable isotope composition within and among buckthorn plants. Further, the 15N signal in buckthorn varied predictably with soil composition. However, lack of sufficient differentiation of geographic areas along axes of isotopic and environmental variation appears to preclude the use of carbon and nitrogen isotopic signals as effective predictors of likely aphid overwintering sites. These preliminary data suggest the need for future work that can further account for variability in 13C and 15N within/among buckthorn plants, and that explores the utility of other stable isotopes in assessing likely aphid overwintering sites. PMID:29206134

Does aphid salivation affect phloem sieve element occlusion in vivo?

PubMed

Medina-Ortega, Karla J; Walker, G P

2013-12-01

To protect against loss of photo-assimilate-rich phloem sap, plants have evolved several mechanisms to plug phloem sieve tubes in response to damage. In many Fabaceae, each sieve element contains a discrete proteinaceous body called a forisome, which, in response to damage, rapidly transforms from a condensed configuration that does not impede the flow of sap to a dispersed configuration that plugs the sieve element. Aphids and other specialized phloem sap feeders can ingest phloem sap from a single sieve element for hours or days, and to do this, they must be able to suppress or reverse phloem plugging. A recent study provided in vitro evidence that aphid saliva can reverse forisome plugs. The present study tested this hypothesis in vivo by inducing forisome plugs which triggered aphids to switch behaviour from phloem sap ingestion to salivation into the sieve element. After salivating into the sieve element for various periods of time, the aphids were instantaneously cryofixed (freeze fixed) in situ on their leaf. The state of the forisome was then determined in the penetrated sieve element and in nearby non-penetrated sieve elements which served as controls for sieve elements not subjected to direct aphid salivation. Forisomes were almost always in close contact with the stylet tips and thus came into direct contact with the saliva. Nonetheless, forisome plugs in the penetrated sieve element did not revert back to a non-plugging state any faster than those in neighbouring sieve elements that were not subjected to direct aphid salivation.

Does aphid salivation affect phloem sieve element occlusion in vivo?

PubMed Central

Medina-Ortega, Karla J.

2013-01-01

To protect against loss of photo-assimilate-rich phloem sap, plants have evolved several mechanisms to plug phloem sieve tubes in response to damage. In many Fabaceae, each sieve element contains a discrete proteinaceous body called a forisome, which, in response to damage, rapidly transforms from a condensed configuration that does not impede the flow of sap to a dispersed configuration that plugs the sieve element. Aphids and other specialized phloem sap feeders can ingest phloem sap from a single sieve element for hours or days, and to do this, they must be able to suppress or reverse phloem plugging. A recent study provided in vitro evidence that aphid saliva can reverse forisome plugs. The present study tested this hypothesis in vivo by inducing forisome plugs which triggered aphids to switch behaviour from phloem sap ingestion to salivation into the sieve element. After salivating into the sieve element for various periods of time, the aphids were instantaneously cryofixed (freeze fixed) in situ on their leaf. The state of the forisome was then determined in the penetrated sieve element and in nearby non-penetrated sieve elements which served as controls for sieve elements not subjected to direct aphid salivation. Forisomes were almost always in close contact with the stylet tips and thus came into direct contact with the saliva. Nonetheless, forisome plugs in the penetrated sieve element did not revert back to a non-plugging state any faster than those in neighbouring sieve elements that were not subjected to direct aphid salivation. PMID:24127515

[Control discourses and power relations of yellow fever: Philadelphia in 1793].

PubMed

Kim, Seohyung

2014-12-01

1793 Yellow fever in Philadelphia was the most severe epidemics in the late 18th century in the United States. More than 10% of the population in the city died and many people fled to other cities. The cause of yellow fever in the United States had close relationship with slaves and sugar in Philadelphia. Sugarcane plantation had needed many labors to produce sugar and lots of Africans had to move to America as slaves. In this process, Aëdes aegypti, the vector of yellow fever had migrated to America and the circumstances of ships or cities provided appropriate conditions for its breeding. In this period, the cause of yellow fever could not be established exactly, so suggestions of doctors became entangled in political and intellectual discourses in American society. There was a critical conflict between Jeffersonian Republicanism and Federalism about the origin and treatment of yellow fever. Benjamin Rush, a Jeffersonian Republican, suggested urban sanitation reform and bloodletting. He believed the infectious disease happened because of unsanitary city condition, so he thought the United States could be a healthy nation by improvement of the public health and sanitation. He would like to cope with national crisis and develop American society on the basis of republicanism. While Rush suggested the improvement of public health and sanitation, the city government of Philadelphia suggested isolation of yellow fever patients and quarantine. City government isolated the patients from healthy people and it reconstructed space of hospital. Also, it built orphanages to take care of children who lost their parents during the epidemic and implemented power to control people put in the state of exception. Of course, city government tried to protect the city and nation by quarantine of every ship to Philadelphia. Control policies of yellow fever in 1793 showed different conflicts and interactions. Through the yellow fever, Jeffersonian Republicanism and Federalism had

SOYBEAN.APHID.SD.2017

USDA-ARS?s Scientific Manuscript database

Infestations by soybean aphid (SA) can reduce soybean yield. Thus, SA-resistant soybean may be useful in reducing infestations and limiting yield loss. Expression of resistance was characterized among 746 soybean accessions in 56 growth chamber tests at the North Central Agricultural Research Labo...

Tracking the global dispersal of a cosmopolitan insect pest, the peach potato aphid

PubMed Central

Margaritopoulos, John T; Kasprowicz, Louise; Malloch, Gaynor L; Fenton, Brian

2009-01-01

Background Global commerce and human transportation are responsible for the range expansion of various insect pests such as the plant sucking aphids. High resolution DNA markers provide the opportunity to examine the genetic structure of aphid populations, identify aphid genotypes and infer their evolutionary history and routes of expansion which is of value in developing management strategies. One of the most widespread aphid species is the peach-potato aphid Myzus persicae, which is considered as a serious pest on various crops in many parts of the world. The present study examined the genetic variation of this aphid at a world scale and then related this to distribution patterns. In particular, 197 aphid parthenogenetic lineages from around the world were analysed with six microsatellite loci. Results Bayesian clustering and admixture analysis split the aphid genotypes into three genetic clusters: European M. persicae persicae, New Zealand M. persicae persicae and Global M. persicae nicotianae. This partition was supported by FST and genetic distance analyses. The results showed two further points, a possible connection between genotypes found in the UK and New Zealand and globalization of nicotianae associated with colonisation of regions where tobacco is not cultivated. In addition, we report the presence of geographically widespread clones and for the first time the presence of a nicotianae genotype in the Old and New World. Lastly, heterozygote deficiency was detected in some sexual and asexual populations. Conclusion The study revealed important genetic variation among the aphid populations we examined and this was partitioned according to region and host-plant. Clonal selection and gene flow between sexual and asexual lineages are important factors shaping the genetic structure of the aphid populations. In addition, the results reflected the globalization of two subspecies of M. persicae with successful clones being spread at various scales throughout the

Registration of "CPSG-3481 sugarcane

USDA-ARS?s Scientific Manuscript database

‘CPSG-3481’ (Reg. No. , PI 676023) sugarcane (a complex hybrid of Saccharum spp.) was a new cultivar developed through cooperative research conducted by the Shakarganj Sugar Research Institute in Pakistan and the USDA-ARS Sugarcane Field Station in USA, and released to growers for loam soils...

Trichoderma harzianum enhances tomato indirect defense against aphids.

PubMed

Coppola, Mariangela; Cascone, Pasquale; Chiusano, Maria Luisa; Colantuono, Chiara; Lorito, Matteo; Pennacchio, Francesco; Rao, Rosa; Woo, Sheridan Lois; Guerrieri, Emilio; Digilio, Maria Cristina

2017-12-01

Many fungal root symbionts of the genus Trichoderma are well-known for their beneficial effects on agronomic performance and protection against plant pathogens; moreover, they may enhance protection from insect pests, by triggering plant resistance mechanisms. Defense barriers against insects are induced by the activation of metabolic pathways involved in the production of defense-related plant compounds, either directly active against herbivore insects, or exerting an indirect effect, by increasing the attraction of herbivore natural enemies. In a model system composed of the tomato plant, the aphid Macrosiphum euphorbiae and the parasitoid Aphidius ervi, plant metabolic changes induced by Trichoderma harzianum and their effects on higher trophic levels have been assessed. T. harzianum T22 treatments induce a primed state that upon aphid attacks leads to an increased attraction of aphid parasitoids, mediated by the enhanced production of volatile organic compounds (VOCs) that are known to induce Aphidius ervi flight. Transcriptome sequencing of T22-treated plants infested by aphids showed a remarkable upregulation of genes involved in terpenoids biosynthesis and salicylic acid pathway, which are consistent with the observed flight response of A. ervi and the VOC bouquet profile underlying this behavioral response. © 2017 Institute of Zoology, Chinese Academy of Sciences.

Indirect effect of a transgenic wheat on aphids through enhanced powdery mildew resistance.

PubMed

von Burg, Simone; Álvarez-Alfageme, Fernando; Romeis, Jörg

2012-01-01

In agricultural ecosystems, arthropod herbivores and fungal pathogens are likely to colonise the same plant and may therefore affect each other directly or indirectly. The fungus that causes powdery mildew (Blumeria graminis tritici) and cereal aphids are important pests of wheat but interactions between them have seldom been investigated. We studied the effects of powdery mildew of wheat on two cereal aphid species, Metopolophium dirhodum and Rhopalosiphum padi. We hypothesized that aphid number and size will be smaller on powdery mildew-infected plants than on non-infected plants. In a first experiment we used six commercially available wheat varieties whereas in the second experiment we used a genetically modified (GM) mildew-resistant wheat line and its non-transgenic sister line. Because the two lines differed only in the presence of the transgene and in powdery mildew resistance, experiment 2 avoided the confounding effect of variety. In both experiments, the number of M. dirhodum but not of R. padi was reduced by powdery mildew infection. Transgenic mildew-resistant lines therefore harboured bigger aphid populations than the non-transgenic lines. For both aphid species individual size was mostly influenced by aphid number. Our results indicate that plants that are protected from a particular pest (powdery mildew) became more favourable for another pest (aphids).

Indirect Effect of a Transgenic Wheat on Aphids through Enhanced Powdery Mildew Resistance

PubMed Central

von Burg, Simone; Álvarez-Alfageme, Fernando; Romeis, Jörg

2012-01-01

In agricultural ecosystems, arthropod herbivores and fungal pathogens are likely to colonise the same plant and may therefore affect each other directly or indirectly. The fungus that causes powdery mildew (Blumeria graminis tritici) and cereal aphids are important pests of wheat but interactions between them have seldom been investigated. We studied the effects of powdery mildew of wheat on two cereal aphid species, Metopolophium dirhodum and Rhopalosiphum padi. We hypothesized that aphid number and size will be smaller on powdery mildew-infected plants than on non-infected plants. In a first experiment we used six commercially available wheat varieties whereas in the second experiment we used a genetically modified (GM) mildew-resistant wheat line and its non-transgenic sister line. Because the two lines differed only in the presence of the transgene and in powdery mildew resistance, experiment 2 avoided the confounding effect of variety. In both experiments, the number of M. dirhodum but not of R. padi was reduced by powdery mildew infection. Transgenic mildew-resistant lines therefore harboured bigger aphid populations than the non-transgenic lines. For both aphid species individual size was mostly influenced by aphid number. Our results indicate that plants that are protected from a particular pest (powdery mildew) became more favourable for another pest (aphids). PMID:23056284

Water Stress Modulates Soybean Aphid Performance, Feeding Behavior, and Virus Transmission in Soybean

PubMed Central

Nachappa, Punya; Culkin, Christopher T.; Saya, Peter M.; Han, Jinlong; Nalam, Vamsi J.

2016-01-01

Little is known about how water stress including drought and flooding modifies the ability of plants to resist simultaneous attack by insect feeding and transmission of insect-vectored pathogen. We analyzed insect population growth, feeding behaviors, virus transmission, and plant amino acid profiles and defense gene expression to characterize mechanisms underlying the interaction between water stress, soybean aphid and aphid-transmitted, Soybean mosaic virus, on soybean plants. Population growth of non-viruliferous aphids was reduced under drought stress and saturation, likely because the aphids spent less time feeding from the sieve element on these plants compared to well-watered plants. Water stress did not impact population growth of viruliferous aphids. However, virus incidence and transmission rate was lowest under drought stress and highest under saturated conditions since viruliferous aphids took the greatest amount time to puncture cells and transmit the virus under saturated conditions and lowest time under drought stress. Petiole exudates from drought-stressed plants had the highest level of total free amino acids including asparagine and valine that are critical for aphid performance. Aphids did not benefit from improved phloem sap quality as indicated by their lower densities on drought-stressed plants. Saturation, on the other hand, resulted in low amino acid content compared to all of the other treatments. Drought and saturation had significant and opposing effects on expression of marker genes involved in abscisic acid (ABA) signaling. Drought alone significantly increased expression of ABA marker genes, which likely led to suppression of salicylic acid (SA)- and jasmonic acid (JA)-related genes. In contrast, ABA marker genes were down-regulated under saturation, while expression of SA- and JA-related genes was up-regulated. We propose that the apparent antagonism between ABA and SA/JA signaling pathways contributed to an increase in aphid

Soil pathogen-aphid interactions under differences in soil organic matter and mineral fertilizer.

PubMed

van Gils, Stijn; Tamburini, Giovanni; Marini, Lorenzo; Biere, Arjen; van Agtmaal, Maaike; Tyc, Olaf; Kos, Martine; Kleijn, David; van der Putten, Wim H

2017-01-01

There is increasing evidence showing that microbes can influence plant-insect interactions. In addition, various studies have shown that aboveground pathogens can alter the interactions between plants and insects. However, little is known about the role of soil-borne pathogens in plant-insect interactions. It is also not known how environmental conditions, that steer the performance of soil-borne pathogens, might influence these microbe-plant-insect interactions. Here, we studied effects of the soil-borne pathogen Rhizoctonia solani on aphids (Sitobion avenae) using wheat (Triticum aestivum) as a host. In a greenhouse experiment, we tested how different levels of soil organic matter (SOM) and fertilizer addition influence the interactions between plants and aphids. To examine the influence of the existing soil microbiome on the pathogen effects, we used both unsterilized field soil and sterilized field soil. In unsterilized soil with low SOM content, R. solani addition had a negative effect on aphid biomass, whereas it enhanced aphid biomass in soil with high SOM content. In sterilized soil, however, aphid biomass was enhanced by R. solani addition and by high SOM content. Plant biomass was enhanced by fertilizer addition, but only when SOM content was low, or in the absence of R. solani. We conclude that belowground pathogens influence aphid performance and that the effect of soil pathogens on aphids can be more positive in the absence of a soil microbiome. This implies that experiments studying the effect of pathogens under sterile conditions might not represent realistic interactions. Moreover, pathogen-plant-aphid interactions can be more positive for aphids under high SOM conditions. We recommend that soil conditions should be taken into account in the study of microbe-plant-insect interactions.

Prey foraging by Hippodamia convergens for cereal aphids on wheat

USDA-ARS?s Scientific Manuscript database

We investigated predation by adult convergent lady beetle, Hippodamia convergens Guerin-Meneville, on English grain aphid, Sitobion avenae L., on wheat, Triticum aestivum L., plants in a laboratory arena, and developed a functional response model for the number of aphids eaten by an adult female con...

Detection of novel QTLs for foxglove aphid resistance in soybean

USDA-ARS?s Scientific Manuscript database

Foxglove aphid, Aulacorthum solani (Kaltenbach), is a Hemipteran insect that infected a wide variety of plants worldwide and caused serious yield losses in crops. The objective of this study was to identify the putative QTL for foxglove aphid resistance in wild soybean, PI 366121, (Glycine soja Sieb...

Microorganisms from aphid honeydew attract and enhance the efficacy of natural enemies

PubMed Central

Leroy, Pascal D.; Sabri, Ahmed; Heuskin, Stéphanie; Thonart, Philippe; Lognay, Georges; Verheggen, François J.; Francis, Frédéric; Brostaux, Yves; Felton, Gary W.; Haubruge, Eric

2011-01-01

Aphids are one of the most serious pests of crops worldwide, causing major yield and economic losses. To control aphids, natural enemies could be an option but their efficacy is sometimes limited by their dispersal in natural environment. Here we report the first isolation of a bacterium from the pea aphid Acyrthosiphon pisum honeydew, Staphylococcus sciuri, which acts as a kairomone enhancing the efficiency of aphid natural enemies. Our findings represent the first case of a host-associated bacterium driving prey location and ovipositional preference for the natural enemy. We show that this bacterium has a key role in tritrophic interactions because it is the direct source of volatiles used to locate prey. Some specific semiochemicals produced by S. sciuri were also identified as significant attractants and ovipositional stimulants. The use of this host-associated bacterium could certainly provide a novel approach to control aphids in field and greenhouse systems. PMID:21673669

SOYBEAN.APHID.LH.2009

USDA-ARS?s Scientific Manuscript database

Expression of soybean aphid (SA) resistance was characterized among 496 soybean lines in a twice-replicated field-plot test at the Eastern South Dakota Soil and Water Research Farm near Brookings, SD, in 2009. Natural infestations of SA occurred but were supplemented by placing individual stems of ...

A multi-disciplinary approach to sugarcane research at the USDA, ARS, Sugarcane Research Unit in Houma

USDA-ARS?s Scientific Manuscript database

The mission of the Sugarcane Research Unit (SRU) is to provide research-based solutions that enhance the viability of domestic sugarcane industry. To accomplish this mission, SRU uses a multidisciplinary approach to develop improved varieties and environmentally friendly production strategies. Cons...

Aphid watery saliva counteracts sieve-tube occlusion: a universal phenomenon?

PubMed

Will, Torsten; Kornemann, Sarah R; Furch, Alexandra C U; Tjallingii, W Fred; van Bel, Aart J E

2009-10-01

Ca2+-binding proteins in the watery saliva of Megoura viciae counteract Ca2+-dependent occlusion of sieve plates in Vicia faba and so prevent the shut-down of food supply in response to stylet penetration. The question arises whether this interaction between aphid saliva and sieve-element proteins is a universal phenomenon as inferred by the coincidence between sieve-tube occlusion and salivation. For this purpose, leaf tips were burnt in a number of plant species from four different families to induce remote sieve-plate occlusion. Resultant sieve-plate occlusion in these plant species was counteracted by an abrupt switch of aphid behaviour. Each of the seven aphid species tested interrupted its feeding behaviour and started secreting watery saliva. The protein composition of watery saliva appeared strikingly different between aphid species with less than 50% overlap. Secretion of watery saliva seems to be a universal means to suppress sieve-plate occlusion, although the protein composition of watery saliva seems to diverge between species.

Transgenic Sugarcane with a cry1Ac Gene Exhibited Better Phenotypic Traits and Enhanced Resistance against Sugarcane Borer

PubMed Central

Gao, Shiwu; Yang, Yingying; Wang, Chunfeng; Guo, Jinlong; Zhou, Dinggang; Wu, Qibin; Su, Yachun; Xu, Liping

2016-01-01

We developed sugarcane plants with improved resistance to the sugarcane borer, Diatraea saccharalis (F). An expression vector pGcry1Ac0229, harboring the cry1Ac gene and the selectable marker gene, bar, was constructed. This construct was introduced into the sugarcane cultivar FN15 by particle bombardment. Transformed plantlets were identified after selection with Phosphinothricin (PPT) and Basta. Plantlets were then screened by PCR based on the presence of cry1Ac and 14 cry1Ac positive plantlets were identified. Real-time quantitative PCR (RT-qPCR) revealed that the copy number of cry1Ac gene in the transgenic lines varied from 1 to 148. ELISA analysis showed that Cry1Ac protein levels in 7 transgenic lines ranged from 0.85 μg/FWg to 70.92 μg/FWg in leaves and 0.04 μg/FWg to 7.22 μg/FWg in stems, and negatively correlated to the rate of insect damage that ranged from 36.67% to 13.33%, respectively. Agronomic traits of six transgenic sugarcane lines with medium copy numbers were similar to the non-transgenic parental line. However, phenotype was poor in lines with high or low copy numbers. Compared to the non-transgenic control plants, all transgenic lines with medium copy numbers had relatively equal or lower sucrose yield and significantly improved sugarcane borer resistance, which lowered susceptibility to damage by insects. This suggests that the transgenic sugarcane lines harboring medium copy numbers of the cry1Ac gene may have significantly higher resistance to sugarcane borer but the sugarcane yield in these lines is similar to the non-transgenic control thus making them superior to the control lines. PMID:27093437

AmeriFlux US-SuS Maui Sugarcane Lee/Sheltered

DOE Data Explorer

Anderson, Ray [USDA-Agricultural Research Service, United States Salinity Laboratory, Contaminant Fate and Transport Unit; Wang, Dong [USDA - Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, Water Management Research Unit

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site US-SuS Maui Sugarcane Lee/Sheltered. Site Description - Continuous, irrigated, sugarcane cultivation for >100 years. Practice is to grow plant sugarcane for 2 years, drydown, burn leaves, harvest cane, and then till and replant very shortly after harvest. First cycle of observations were from July 2011 to November 2012. Second cycle was from April 2013 to December 2013. Site differs from Sugarcane Windy and Sugarcane Middle in soil type and meteorology.

Identification, Characterization and Full-Length Sequence Analysis of a Novel Polerovirus Associated with Wheat Leaf Yellowing Disease

PubMed Central

Zhang, Peipei; Liu, Yan; Liu, Wenwen; Cao, Mengji; Massart, Sebastien; Wang, Xifeng

2017-01-01

To identify the pathogens responsible for leaf yellowing symptoms on wheat samples collected from Jinan, China, we tested for the presence of three known barley/wheat yellow dwarf viruses (BYDV-GAV, -PAV, WYDV-GPV) (most likely pathogens) using RT-PCR. A sample that tested negative for the three viruses was selected for small RNA sequencing. Twenty-five million sequences were generated, among which 5% were of viral origin. A novel polerovirus was discovered and temporarily named wheat leaf yellowing-associated virus (WLYaV). The full genome of WLYaV corresponds to 5,772 nucleotides (nt), with six AUG-initiated open reading frames, one non-AUG-initiated open reading frame, and three untranslated regions, showing typical features of the family Luteoviridae. Sequence comparison and phylogenetic analyses suggested that WLYaV had the closest relationship with sugarcane yellow leaf virus (ScYLV), but the identities of full genomic nucleotides and deduced amino acid sequence of coat protein (CP) were 64.9 and 86.2%, respectively, below the species demarcation thresholds (90%) in the family Luteoviridae. Furthermore, agroinoculation of Nicotiana benthamiana leaves with a cDNA clone of WLYaV caused yellowing symptoms on the plant. Our study adds a new polerovirus that is associated with wheat leaf yellowing disease, which would help to identify and control pathogens of wheat. PMID:28932215

Identification, Characterization and Full-Length Sequence Analysis of a Novel Polerovirus Associated with Wheat Leaf Yellowing Disease.

PubMed

Zhang, Peipei; Liu, Yan; Liu, Wenwen; Cao, Mengji; Massart, Sebastien; Wang, Xifeng

2017-01-01

To identify the pathogens responsible for leaf yellowing symptoms on wheat samples collected from Jinan, China, we tested for the presence of three known barley/wheat yellow dwarf viruses (BYDV-GAV, -PAV, WYDV-GPV) (most likely pathogens) using RT-PCR. A sample that tested negative for the three viruses was selected for small RNA sequencing. Twenty-five million sequences were generated, among which 5% were of viral origin. A novel polerovirus was discovered and temporarily named wheat leaf yellowing-associated virus (WLYaV). The full genome of WLYaV corresponds to 5,772 nucleotides (nt), with six AUG-initiated open reading frames, one non-AUG-initiated open reading frame, and three untranslated regions, showing typical features of the family Luteoviridae . Sequence comparison and phylogenetic analyses suggested that WLYaV had the closest relationship with sugarcane yellow leaf virus (ScYLV), but the identities of full genomic nucleotides and deduced amino acid sequence of coat protein (CP) were 64.9 and 86.2%, respectively, below the species demarcation thresholds (90%) in the family Luteoviridae . Furthermore, agroinoculation of Nicotiana benthamiana leaves with a cDNA clone of WLYaV caused yellowing symptoms on the plant. Our study adds a new polerovirus that is associated with wheat leaf yellowing disease, which would help to identify and control pathogens of wheat.

Water Stress and Aphid Feeding Differentially Influence Metabolite Composition in Arabidopsis thaliana (L.)

PubMed Central

Mewis, Inga; Khan, Mohammed A. M.; Glawischnig, Erich; Schreiner, Monika; Ulrichs, Christian

2012-01-01

Little is known about how drought stress influences plant secondary metabolite accumulation and how this affects plant defense against different aphids. We therefore cultivated Arabidopsis thaliana (L.) plants under well-watered, drought, and water-logged conditions. Two aphid species were selected for this study: the generalist Myzus persicae (Sulzer) and the crucifer specialist Brevicoryne brassicae (L.). Metabolite concentrations in the phloem sap, which influence aphid growth, changed particularly under drought stress. Levels of sucrose and several amino acids, such as glutamic acid, proline, isoleucine, and lysine increased, while concentrations of 4-methoxyindol-3-ylmethyl glucosinolate decreased. M. persicae population growth was highest on plants under drought stress conditions. However, B. brassicae did not profit from improved phloem sap quality under drought stress and performed equally in all water treatments. Water stress and aphids generally had an opposite effect on the accumulation of secondary metabolites in the plant rosettes. Drought stress and water-logging led to increased aliphatic glucosinolate and flavonoid levels. Conversely, aphid feeding, especially of M. persicae, reduced levels of flavonoids and glucosinolates in the plants. Correspondingly, transcript levels of aliphatic biosynthetic genes decreased after feeding of both aphid species. Contrary to M. persicae, drought stress did not promote population growth of B. brassicae on these plants. The specialist aphid induced expression of CYP79B2, CYP79B3, and PAD3 with corresponding accumulation of indolyl glucosinolates and camalexin. This was distinct from M. persicae, which did not elicit similarly strong camalexin accumulation, which led to the hypothesis of a specific defense adaptations against the specialist aphid. PMID:23144921

Application of plant growth regulators mitigates chlorotic foliar injury by the black pecan aphid (Hemiptera: Aphididae).

PubMed

Cottrell, Ted E; Wood, Bruce W; Ni, Xinzhi

2010-11-01

Black pecan aphid, Melanocallis caryaefoliae (Davis) (Hemiptera: Aphididae), feeding elicits localized chlorotic injury to pecan foliage [Carya illinoinensis (Wangenh.) K Koch] and apparent acceleration of leaf senescence and defoliation. The ability of certain plant growth regulators (PGRs) (forchlorfenuron, gibberellic acid and aviglycine) to prevent M. caryaefoliae from triggering pecan leaf chlorosis and senescence-like processes was evaluated on two dates in both 2006 and 2007. Treatments were applied to orchard foliage and used in laboratory leaf-disc bioassays to assess possible reduction in aphid-elicited chlorosis and concomitant effects on aphid mortality and development. Foliage pretreated with forchlorfenuron + gibberellic acid prior to being challenged with aphids resulted in significantly less aphid-elicited chlorosis than did control or aviglycine-treated leaf discs. No PGR affected aphid mortality; however, development time was increased by forchlorfenuron + gibberellic acid in 2006 and by aviglycine + gibberellic acid on one date in 2007. Certain PGRs possess the potential for usage on pecan to protect foliar canopies from M. caryaefoliae via changes in the susceptibility of the host leaf to senescence-like factors being introduced by feeding aphids. This protective effect on host foliage and the associated suppressive effect on development of feeding aphids might also be relevant to pest management programs on other aphid-crop systems in which aphid-elicited chlorosis and senescence-like processes can limit profitability. Published 2010 by John Wiley & Sons, Ltd.

Arabidopsis thaliana—Myzus persicae interaction: shaping the understanding of plant defense against phloem-feeding aphids

PubMed Central

Louis, Joe; Shah, Jyoti

2013-01-01

The phloem provides a unique niche for several organisms. Aphids are a large group of Hemipteran insects that utilize stylets present in their mouthparts to pierce sieve elements and drink large volumes of phloem sap. In addition, many aphids also vector viral diseases. Myzus persicae, commonly known as the green peach aphid (GPA), is an important pest of a large variety of plants that includes Arabidopsis thaliana. This review summarizes recent studies that have exploited the compatible interaction between Arabidopsis and GPA to understand the molecular and physiological mechanisms utilized by plants to control aphid infestation, as well as genes and mechanisms that contribute to susceptibility. In addition, recent efforts to identify aphid-delivered elicitors of plant defenses and novel aphid salivary components that facilitate infestation are also discussed. PMID:23847627

Low bacterial community diversity in two introduced aphid pests revealed with 16S rRNA amplicon sequencing

PubMed Central

Ortiz-Martínez, Sebastían; Silva, Andrea X.; Lavandero, Blas

2018-01-01

Bacterial endosymbionts that produce important phenotypic effects on their hosts are common among plant sap-sucking insects. Aphids have become a model system of insect-symbiont interactions. However, endosymbiont research has focused on a few aphid species, making it necessary to make greater efforts to other aphid species through different regions, in order to have a better understanding of the role of endosymbionts in aphids as a group. Aphid endosymbionts have frequently been studied by PCR-based techniques, using species-specific primers, nevertheless this approach may omit other non-target bacteria cohabiting a particular host species. Advances in high-throughput sequencing technologies are complementing our knowledge of microbial communities by allowing us the study of whole microbiome of different organisms. We used a 16S rRNA amplicon sequencing approach to study the microbiome of aphids in order to describe the bacterial community diversity in introduced populations of the cereal aphids, Sitobion avenae and Rhopalosiphum padi in Chile (South America). An absence of secondary endosymbionts and two common secondary endosymbionts of aphids were found in the aphids R. padi and S. avenae, respectively. Of those endosymbionts, Regiella insecticola was the dominant secondary endosymbiont among the aphid samples. In addition, the presence of a previously unidentified bacterial species closely related to a phytopathogenic Pseudomonad species was detected. We discuss these results in relation to the bacterial endosymbiont diversity found in other regions of the native and introduced range of S. avenae and R. padi. A similar endosymbiont diversity has been reported for both aphid species in their native range. However, variation in the secondary endosymbiont infection could be observed among the introduced and native populations of the aphid S. avenae, indicating that aphid-endosymbiont associations can vary across the geographic range of an aphid species. In

Sugarcane

USDA-ARS?s Scientific Manuscript database

Sugarcane is one of the most important crops globally, providing most of the world’s sugar and bio-energy (ethanol and electricity). This contribution has been underpinned by the successful introgression of genes from wild germplasm, particularly from Saccharum spontaneum, by breeders in the early 1...

Transcriptome profilng of defense responses to aphid feeding in wheat

USDA-ARS?s Scientific Manuscript database

Greenbug (Schizaphis graminum) is a serious aphid pest in small grain crops in the southern Great Plains of the US. We are trying to understand the molecular mechanisms of host resistance against aphid infestation in the grass genome using wheat-greenbug as a model system. In the present study, a mi...

Large-scale gene discovery in the pea aphid Acyrthosiphon pisum (Hemiptera)

PubMed Central

Sabater-Muñoz, Beatriz; Legeai, Fabrice; Rispe, Claude; Bonhomme, Joël; Dearden, Peter; Dossat, Carole; Duclert, Aymeric; Gauthier, Jean-Pierre; Ducray, Danièle Giblot; Hunter, Wayne; Dang, Phat; Kambhampati, Srini; Martinez-Torres, David; Cortes, Teresa; Moya, Andrès; Nakabachi, Atsushi; Philippe, Cathy; Prunier-Leterme, Nathalie; Rahbé, Yvan; Simon, Jean-Christophe; Stern, David L; Wincker, Patrick; Tagu, Denis

2006-01-01

Aphids are the leading pests in agricultural crops. A large-scale sequencing of 40,904 ESTs from the pea aphid Acyrthosiphon pisum was carried out to define a catalog of 12,082 unique transcripts. A strong AT bias was found, indicating a compositional shift between Drosophila melanogaster and A. pisum. An in silico profiling analysis characterized 135 transcripts specific to pea-aphid tissues (relating to bacteriocytes and parthenogenetic embryos). This project is the first to address the genetics of the Hemiptera and of a hemimetabolous insect. PMID:16542494

Preparing soft-bodied arthropods for microscope examination: Aphids (Insecta: Hemiptera: Aphididae)

USDA-ARS?s Scientific Manuscript database

Proper identification of aphids (Hemiptera: Aphididae) require preparation of the specimen on a microscope slide. This training video provides visual instruction on how to prepare aphid specimens on microscope slides for examination and indentification. Steps ranging from collection, specimen clear...

Circulative Nonpropagative Aphid Transmission of Nanoviruses: an Oversimplified View

PubMed Central

Sicard, Anne; Zeddam, Jean-Louis; Yvon, Michel; Michalakis, Yannis; Gutiérrez, Serafin

2015-01-01

ABSTRACT Plant virus species of the family Nanoviridae have segmented genomes with the highest known number of segments encapsidated individually. They thus likely represent the most extreme case of the so-called multipartite, or multicomponent, viruses. All species of the family are believed to be transmitted in a circulative nonpropagative manner by aphid vectors, meaning that the virus simply crosses cellular barriers within the aphid body, from the gut to the salivary glands, without replicating or even expressing any of its genes. However, this assumption is largely based on analogy with the transmission of other plant viruses, such as geminiviruses or luteoviruses, and the details of the molecular and cellular interactions between aphids and nanoviruses are poorly investigated. When comparing the relative frequencies of the eight genome segments in populations of the species Faba bean necrotic stunt virus (FBNSV) (genus Nanovirus) within host plants and within aphid vectors fed on these plants, we unexpectedly found evidence of reproducible changes in the frequencies of some specific segments. We further show that these changes occur within the gut during early stages of the virus cycle in the aphid and not later, when the virus is translocated into the salivary glands. This peculiar observation, which was similarly confirmed in three aphid vector species, Acyrthosiphon pisum, Aphis craccivora, and Myzus persicae, calls for revisiting of the mechanisms of nanovirus transmission. It reveals an unexpected intimate interaction that may not fit the canonical circulative nonpropagative transmission. IMPORTANCE A specific mode of interaction between viruses and arthropod vectors has been extensively described in plant viruses in the three families Luteoviridae, Geminiviridae, and Nanoviridae, but never in arboviruses of animals. This so-called circulative nonpropagative transmission contrasts with the classical biological transmission of animal arboviruses in that

Spectral Detection of Soybean Aphid (Hemiptera: Aphididae) and Confounding Insecticide Effects in Soybean

NASA Astrophysics Data System (ADS)

Alves, Tavvs Micael

Soybean aphid, Aphis glycines (Hemiptera: Aphididae) is the primary insect pest of soybean in the northcentral United States. Soybean aphid may cause stunted plants, leaf discoloration, plant death, and decrease soybean yield by 40%. Sampling plans have been developed for supporting soybean aphid management. However, growers' perception about time involved in direct insect counts has been contributing to a lower adoption of traditional pest scouting methods and may be associated with the use of prophylactic insecticide applications in soybean. Remote sensing of plant spectral (light-derived) responses to soybean aphid feeding is a promising alternative to estimate injury without direct insect counts and, thus, increase adoption and efficiency of scouting programs. This research explored the use of remote sensing of soybean reflectance for detection of soybean aphids and showed that foliar insecticides may have implications for subsequent use of soybean spectral reflectance for pest detection. (Abstract shortened by ProQuest.).

Large-scale label-free quantitative proteomics of the pea aphid-Buchnera symbiosis.

PubMed

Poliakov, Anton; Russell, Calum W; Ponnala, Lalit; Hoops, Harold J; Sun, Qi; Douglas, Angela E; van Wijk, Klaas J

2011-06-01

Many insects are nutritionally dependent on symbiotic microorganisms that have tiny genomes and are housed in specialized host cells called bacteriocytes. The obligate symbiosis between the pea aphid Acyrthosiphon pisum and the γ-proteobacterium Buchnera aphidicola (only 584 predicted proteins) is particularly amenable for molecular analysis because the genomes of both partners have been sequenced. To better define the symbiotic relationship between this aphid and Buchnera, we used large-scale, high accuracy tandem mass spectrometry (nanoLC-LTQ-Orbtrap) to identify aphid and Buchnera proteins in the whole aphid body, purified bacteriocytes, isolated Buchnera cells and the residual bacteriocyte fraction. More than 1900 aphid and 400 Buchnera proteins were identified. All enzymes in amino acid metabolism annotated in the Buchnera genome were detected, reflecting the high (68%) coverage of the proteome and supporting the core function of Buchnera in the aphid symbiosis. Transporters mediating the transport of predicted metabolites were present in the bacteriocyte. Label-free spectral counting combined with hierarchical clustering, allowed to define the quantitative distribution of a subset of these proteins across both symbiotic partners, yielding no evidence for the selective transfer of protein among the partners in either direction. This is the first quantitative proteome analysis of bacteriocyte symbiosis, providing a wealth of information about molecular function of both the host cell and bacterial symbiont.

A guide to the winged aphids (Homoptera) of Costa Rica.

PubMed

Voegtlin, David; Villalobos, William; Sánchez, Marco Vinicio; Saborio-R, Guido; Rivera, Carmen

2003-05-01

This guide is a compilation of limited morphological and biological information on the winged morphs of 60 species of aphids that have been collected in Costa Rica. It should not be viewed as a definitive taxonomic treatise on the aphids of Costa Rica, rather it is a tool that can be used to assist in research on the biology, host plant relationships, taxonomy, and virus transmission capabilities of aphids. Each species is covered in an identical manner. Morphological and biological information is provided in both Spanish and English as well as photographs of slide mounted specimens. Keys are provided to help the user in identifying the species. Most of the specimens examined were taken in traps associated with epidemiological studies. Limited field collecting has generated host records and these have been added to a list of the aphids of Central America that was compiled by Pamela Anderson and appended in the guide with her permission. The authors hope that this book will be useful to entomologists in Costa Rica and Central America.

Comparison of transmission efficiency of different isolates of Potato virus Y among three aphid vectors

USDA-ARS?s Scientific Manuscript database

Potato virus Y (PVY) strains are transmitted by different aphid species in a non-persistent, non-circulative manner. Green peach aphid (GPA, Myzus persicae Sulzer; Aphididae, Macrosiphini) is the most efficient vector in laboratory studies, but potato aphid (PA, Macrosiphum euphorbiae Thomas; Aphidi...

Overexpression and Down-Regulation of Barley Lipoxygenase LOX2.2 Affects Jasmonate-Regulated Genes and Aphid Fecundity

PubMed Central

Losvik, Aleksandra; Beste, Lisa; Glinwood, Robert; Ivarson, Emelie; Stephens, Jennifer; Zhu, Li-Hua; Jonsson, Lisbeth

2017-01-01

Aphids are pests on many crops and depend on plant phloem sap as their food source. In an attempt to find factors improving plant resistance against aphids, we studied the effects of overexpression and down-regulation of the lipoxygenase gene LOX2.2 in barley (Hordeum vulgare L.) on the performance of two aphid species. A specialist, bird cherry-oat aphid (Rhopalosiphum padi L.) and a generalist, green peach aphid (Myzus persicae Sulzer) were studied. LOX2.2 overexpressing lines showed up-regulation of some other jasmonic acid (JA)-regulated genes, and antisense lines showed down-regulation of such genes. Overexpression or suppression of LOX2.2 did not affect aphid settling or the life span on the plants, but in short term fecundity tests, overexpressing plants supported lower aphid numbers and antisense plants higher aphid numbers. The amounts and composition of released volatile organic compounds did not differ between control and LOX2.2 overexpressing lines. Up-regulation of genes was similar for both aphid species. The results suggest that LOX2.2 plays a role in the activation of JA-mediated responses and indicates the involvement of LOX2.2 in basic defense responses. PMID:29257097

Phytochemical profile of sugarcane and its potential health aspects

PubMed Central

Singh, Amandeep; Lal, Uma Ranjan; Mukhtar, Hayat Muhammad; Singh, Prabh Simran; Shah, Gagan; Dhawan, Ravi Kumar

2015-01-01

Sugarcane (Saccharum officinarum Linn.) is an important perennial grass of Poaceae family, indigenous to tropical South Asia and Southeast Asia. It is cultivated worldwide due to the economical and medicinal value of its high yielding products. Sugarcane juice is well known as a raw material for the production of refined sugar and its wax is considered as a potential substitute for the expensive carnauba wax, which is of cosmetic and pharmaceutical interest. Refined sugar is the primary product of sugarcane juice, but during its processing, various other valuable products are also obtained in an unrefined form, such as, brown sugar, molasses, and jaggery. Sugarcane juice is widely used in India in the treatment of jaundice, hemorrhage, dysuria, anuria, and other urinary diseases. Herein, we have summarized the different phytoconstituents and health benefits of sugarcane and its valuable products. The phytochemistry of sugarcane wax (obtained from the leaves and stalks of sugarcane), leaves, juice, and its products has revealed the presence of various fatty acid, alcohol, phytosterols, higher terpenoids, flavonoids, -O- and -C-glycosides, and phenolic acids. The future prospective of some of the sugarcane products has been discussed, which needs a phytopharmacological study and has a great potential to be a valuable medicinal product. PMID:26009693

Phytochemical profile of sugarcane and its potential health aspects.

PubMed

Singh, Amandeep; Lal, Uma Ranjan; Mukhtar, Hayat Muhammad; Singh, Prabh Simran; Shah, Gagan; Dhawan, Ravi Kumar

2015-01-01

Sugarcane (Saccharum officinarum Linn.) is an important perennial grass of Poaceae family, indigenous to tropical South Asia and Southeast Asia. It is cultivated worldwide due to the economical and medicinal value of its high yielding products. Sugarcane juice is well known as a raw material for the production of refined sugar and its wax is considered as a potential substitute for the expensive carnauba wax, which is of cosmetic and pharmaceutical interest. Refined sugar is the primary product of sugarcane juice, but during its processing, various other valuable products are also obtained in an unrefined form, such as, brown sugar, molasses, and jaggery. Sugarcane juice is widely used in India in the treatment of jaundice, hemorrhage, dysuria, anuria, and other urinary diseases. Herein, we have summarized the different phytoconstituents and health benefits of sugarcane and its valuable products. The phytochemistry of sugarcane wax (obtained from the leaves and stalks of sugarcane), leaves, juice, and its products has revealed the presence of various fatty acid, alcohol, phytosterols, higher terpenoids, flavonoids, -O- and -C-glycosides, and phenolic acids. The future prospective of some of the sugarcane products has been discussed, which needs a phytopharmacological study and has a great potential to be a valuable medicinal product.

Aphid population fluctuations and patterns of species dominance in Puerto Rico

USDA-ARS?s Scientific Manuscript database

Technical Abstract: Papaya ringspot virus (PRSV) is a non-persistently transmitted virus affecting papaya and cucurbit production worldwide. Papaya is not known to be colonized by any species of aphid, but multiple species can transmit the virus. That means that transmission depends on aphid populat...

Identification of conditions for successful aphid control by ladybirds in greenhouses

USDA-ARS?s Scientific Manuscript database

As part of my research on the mass production and augmentative release of ladybirds, I reviewed the primary research literature to test the prediction that ladybirds are effective aphid predators in greenhouses. Aphid population reduction exceeded 50% in most studies and ladybird release rates usual...

Peroxiredoxin 1 protects the pea aphid Acyrthosiphon pisum from oxidative stress induced by Micrococcus luteus infection.

PubMed

Zhang, Yongdong; Lu, Zhiqiang

2015-05-01

Reactive oxygen species (ROSs) are generated in organisms in response to infections caused by invading microbes. However, excessive ROSs will inflict oxidative damage on the host. Peroxiredoxins (Prxs) are antioxidative enzymes that may eliminate ROSs efficiently. In this study, ApPrx1 from the pea aphid Acyrthosiphon pisum was cloned, and its function was investigated in vitro and in vivo. In the presence of DTT, recombinant ApPrx1 protein from Escherichia coli showed antioxidative activity by eliminating H2O2 effectively. The H2O2 levels were significantly higher in Micrococcus luteus-infected aphids than in uninfected aphids, and ApPrx1 expression was remarkably up-regulated when the aphids were infected with M. luteus or injected with H2O2. When ApPrx1 expression was reduced by dsRNA injection, the survival of the aphids decreased significantly after M. luteus infection. Knockdown of ApPrx1 decreased M. luteus loads inside the aphids 48h post-infection. While under infection conditions, the H2O2 levels were much higher in ApPrx1 knockdown aphids than in dsGFP-injected aphids, indicating that the decreased survival of the aphids was caused by increased oxidative stress. Taken together, our results reveal that ApPrx1 plays a protective role in oxidative stress caused by bacterial infection. Copyright © 2015 Elsevier Inc. All rights reserved.

Transcriptome Analysis of Green Peach Aphid (Myzus persicae): Insight into Developmental Regulation and Inter-Species Divergence

PubMed Central

Ji, Rui; Wang, Yujun; Cheng, Yanbin; Zhang, Meiping; Zhang, Hong-Bin; Zhu, Li; Fang, Jichao; Zhu-Salzman, Keyan

2016-01-01

Green peach aphid (Myzus persicae) and pea aphid (Acyrthosiphon pisum) are two phylogenetically closely related agricultural pests. While pea aphid is restricted to Fabaceae, green peach aphid feeds on hundreds of plant species from more than 40 families. Transcriptome comparison could shed light on the genetic factors underlying the difference in host range between the two species. Furthermore, a large scale study contrasting gene expression between immature nymphs and fully developed adult aphids would fill a previous knowledge gap. Here, we obtained transcriptomic sequences of green peach aphid nymphs and adults, respectively, using Illumina sequencing technology. A total of 2244 genes were found to be differentially expressed between the two developmental stages, many of which were associated with detoxification, hormone production, cuticle formation, metabolism, food digestion, and absorption. When searched against publically available pea aphid mRNA sequences, 13,752 unigenes were found to have no homologous counterparts. Interestingly, many of these unigenes that could be annotated in other databases were involved in the “xenobiotics biodegradation and metabolism” pathway, suggesting the two aphids differ in their adaptation to secondary metabolites of host plants. Conversely, 3989 orthologous gene pairs between the two species were subjected to calculations of synonymous and nonsynonymous substitutions, and 148 of the genes potentially evolved in response to positive selection. Some of these genes were predicted to be associated with insect-plant interactions. Our study has revealed certain molecular events related to aphid development, and provided some insight into biological variations in two aphid species, possibly as a result of host plant adaptation. PMID:27812361

An epidemiological model for externally sourced vector-borne viruses applied to Bean yellow mosaic virus in lupin crops in a Mediterranean-type environment.

PubMed

Maling, T; Diggle, A J; Thackray, D J; Siddique, K H M; Jones, R A C

2008-12-01

A hybrid mechanistic/statistical model was developed to predict vector activity and epidemics of vector-borne viruses spreading from external virus sources to an adjacent crop. The pathosystem tested was Bean yellow mosaic virus (BYMV) spreading from annually self-regenerating, legume-based pastures to adjacent crops of narrow-leafed lupin (Lupinus angustifolius) in the winter-spring growing season in a region with a Mediterranean-type environment where the virus persists over summer within dormant seed of annual clovers. The model uses a combination of daily rainfall and mean temperature during late summer and early fall to drive aphid population increase, migration of aphids from pasture to lupin crops, and the spread of BYMV. The model predicted time of arrival of aphid vectors and resulting BYMV spread successfully for seven of eight datasets from 2 years of field observations at four sites representing different rainfall and geographic zones of the southwestern Australian grainbelt. Sensitivity analysis was performed to determine the relative importance of the main parameters that describe the pathosystem. The hybrid mechanistic/statistical approach used created a flexible analytical tool for vector-mediated plant pathosystems that made useful predictions even when field data were not available for some components of the system.

The impacts of climate change and belowground herbivory on aphids via primary metabolites

NASA Astrophysics Data System (ADS)

Ryalls, James M. W.

Global climate and atmospheric change (summarised as climate change for brevity) may alter patterns of crop damage by insect herbivores, but little is known about how multiple climate change factors, acting in tandem, shape such interactions. Crucially, the specific plant-mediated mechanisms underpinning these effects remain largely unknown. Moreover, research into the effects of climate change on leguminous plant species, which have the ability to fix atmospheric nitrogen (N2) via their association with root nodule-dwelling rhizobial bacteria, and their associated insect herbivores, is surprisingly scarce considering their increasing importance in terrestrial ecosystems worldwide. Using a model legume, lucerne, otherwise known as alfalfa, Medicago sativa (Fabaceae), and a model pest species, the pea aphid, Acyrthosiphon pisum (Hemiptera: Aphididae), this work addresses how predicted changes in carbon dioxide (CO2) concentrations, temperature and rainfall patterns as well as interactions with other organisms, including the root-feeding weevil Sitona discoideus (Coleoptera: Curculionidae), might shape legume-feeding aphid populations in the future. Recent literature on the impacts of climate change on aphids and the biology and trophic interactions of lucerne aphids specifically were synthesised in chapters one and two, respectively. These chapters highlighted the importance of the interactions between multiple abiotic and biotic variables in shaping aphid population dynamics. Empirical research chapters three to six, using up to five lucerne genotypes (i.e. cultivars) in glasshouse and field experiments, addressed how A. pisum responded to the isolated and combined effects of climate change and root herbivory. In particular, chapter three determined the effects of elevated temperatures (eT) and elevated atmospheric CO2 concentrations (eCO2) on root-feeding S. discoideus larvae and their interaction with A. pisum. Chapter four addressed whether the effects of eT, e

Mind your elders: wild soybean’s contribution to soybean aphid resistance

USDA-ARS?s Scientific Manuscript database

Currently, biotype 4 soybean aphid (Aphis glycines Matsamura, SBA) is the most virulent SBA biotype. Overcoming the most aphid resistant genes, SBA biotype 4 has become the greatest challenge in utilizing plant resistance in soybean [Glycine max (L.) Merr.]. Soybean’s wild ancestor Glycine soja (Sie...

Elevated Carbon Dioxide Concentration Reduces Alarm Signaling in Aphids.

PubMed

Boullis, Antoine; Fassotte, Bérénice; Sarles, Landry; Lognay, Georges; Heuskin, Stéphanie; Vanderplanck, Maryse; Bartram, Stefan; Haubruge, Eric; Francis, Frédéric; Verheggen, François J

2017-02-01

Insects often rely on olfaction to communicate with conspecifics. While the chemical language of insects has been deciphered in recent decades, few studies have assessed how changes in atmospheric greenhouse gas concentrations might impact pheromonal communication in insects. Here, we hypothesize that changes in the concentration of atmospheric carbon dioxide affect the whole dynamics of alarm signaling in aphids, including: (1) the production of the active compound (E)-β-farnesene (Eβf), (2) emission behavior when under attack, (3) perception by the olfactory apparatus, and (4) the escape response. We reared two strains of the pea aphid, Acyrthosiphon pisum, under ambient and elevated CO 2 concentrations over several generations. We found that an increase in CO 2 concentration reduced the production (i.e., individual content) and emission (released under predation events) of Eβf. While no difference in Eβf neuronal perception was observed, we found that an increase in CO 2 strongly reduced the escape behavior expressed by an aphid colony following exposure to natural doses of alarm pheromone. In conclusion, our results confirm that changes to greenhouse gases impact chemical communication in the pea aphid, and could potentially have a cascade effect on interactions with higher trophic levels.

Ant tending influences soldier production in a social aphid.

PubMed

Shingleton, A W; Foster, W A

2000-09-22

The aphid Pseudoregma sundanica (Van der Goot) (Homoptera: Aphididae) has two defence strategies. It is obligatorily tended by various species of ant and also produces sterile soldiers. We investigated how they allocate their investment in these two strategies. We measured the size, number of soldiers, number and species of tending ant, and number and species of predators in P. sundanica populations. We found that the level of ant tending correlated negatively with soldier investment in P. sundanica. The species of tending ant also influenced soldier investment. We excluded ants from aphid populations and recorded changes in population size and structure over four weeks. Ant exclusion led to population decline and extinction. At the same time, surviving populations showed a significant increase in soldier investment. The data demonstrate that social aphids can adjust their investment in soldiers in direct response to environmental change.

Pathogenic fungi and parasitoids of aphids present in air captures of migratory alates in the low-latitude plateau of Yunnan, China.

PubMed

Huang, Zhi-Hong; Feng, Ming-Guang; Chen, Xue-Xin; Liu, Shu-Sheng

2008-10-01

To survey fungal pathogens and parasitoids of aphids in the low-latitude plateau of Yunnan, southwest China, 3,553 migratory alates of Brevicoryne brassicae, Lipaphis erysimi, and Myzus persicae were attracted to a yellow-plus-plant trap from air during a full-year period and individually reared on cabbage leaves for 7-14 d at 18-22 degrees C and L:D 12:12. Among the trapped alates, 19.2% were killed by 10 species of aphid-pathogenic fungi after survival of 2.3 d (range, 1-7 d). Another 2.8% were mummified by the wasps Aphidius gifuensis, Diaeretella rapae, Ephedrus plagiator, and Aphelinus mali after survival of 4.9 d (range, 1-11 d). Most of the mycosed alates (77.8%) died from Entomophthorales predominated by Pandora neoaphidis (42.7%) and Zoophthora radicans (14.5%), followed by P. nouryi, Neozygites fresenii, Conidiobiolus spp., Entomophthora planchoniana, and Z. aphidis in decreasing frequencies. A mitosporic fungus, Lecanicillium lecanii, was found frequently in L. erysimi alates trapped in rainy season. However, B. brassicae alates captured in dry season were infected or parasitized very occasionally. The predeath fecundity of the infected or parasitized alates warranted successful colonization on plants, although greatly reduced, and was well shown by the fitted probability for a given fecundity per capita and the increasing mean size of their progeny colonies. Contagious transmission of the alate-borne mycosis in most of the colonies caused high progeny mortalities within 14 d. The results highlight for the first time the diversity of aphid pathogens and the spread of both pathogens and parasitoids with host dispersal flight in the low-latitude plateau.

Cannibalism in the pea aphid, Acyrthosiphon pisum.

PubMed

Cooper, Lucy C; Desjonqueres, Camille; Leather, Simon R

2014-12-01

Previous observations of cannibalism have been made in the aphid Acyrthosiphon pisum (L.): this article seeks to quantify factors contributing to such behaviors. We observed and quantified the responses of a number of clones and life stages to varying levels of starvation, in the form of increasingly desiccated Vica faba L. plants (receiving 50, 25, or 10 mL every second day) or a complete absence of host plant. We found that, while the longest incidences of cannibalism are carried out by juveniles (F = 3.45, P = 0.019, df = 3) and targeted at adults, the starvation treatments had the most significant effect on the prevalence of cannibalism in mature A. pisum (F = 2.24, P = 0.025, df = 9). Furthermore, there was no difference between the prevalence or duration of cannibalistic activities within and between different clones (P ≥ 0.05 in all cases), though juveniles were more likely to target unrelated aphids (V = 6 112, P = 0.011), and spent more time feeding on aphids from the same culture (V = 6 062, P = 0.018). © 2013 Institute of Zoology, Chinese Academy of Sciences.

Differential Expression of Superoxide Dismutase Genes in Aphid-Stressed Maize (Zea mays L.) Seedlings

PubMed Central

Sytykiewicz, Hubert

2014-01-01

The aim of this study was to compare the expression patterns of superoxide dismutase genes (sod2, sod3.4, sod9 and sodB) in seedling leaves of the Zea mays L. Tasty Sweet (susceptible) and Ambrozja (relatively resistant) cultivars infested with one of two hemipteran species, namely monophagous Sitobion avenae F. (grain aphid) or oligophagous Rhopalosiphum padi L. (bird cherry-oat aphid). Secondarily, aphid-elicited alternations in the antioxidative capacity towards DPPH (1,1-diphenyl-2-picrylhydrazyl) radical in insect-stressed plants were evaluated. Comprehensive comparison of expression profiles of the four sod genes showed that both insect species evoked significant upregulation of three genes sod2, sod3.4 and sod9). However, aphid infestation affected non-significant fluctuations in expression of sodB gene in seedlings of both maize genotypes. The highest levels of transcript accumulation occurred at 8 h (sod2 and sod3.4) or 24 h (sod9) post-infestation, and aphid-induced changes in the expression of sod genes were more dramatic in the Ambrozja cultivar than in the Tasty Sweet variety. Furthermore, bird cherry-oat aphid colonization had a more substantial impact on levels of DPPH radical scavenging activity in infested host seedlings than grain aphid colonization. Additionally, Ambrozja plants infested by either hemipteran species showed markedly lower antioxidative capacity compared with attacked Tasty Sweet plants. PMID:24722734

Differential expression of superoxide dismutase genes in aphid-stressed maize (Zea mays L.) seedlings.

PubMed

Sytykiewicz, Hubert

2014-01-01

The aim of this study was to compare the expression patterns of superoxide dismutase genes (sod2, sod3.4, sod9 and sodB) in seedling leaves of the Zea mays L. Tasty Sweet (susceptible) and Ambrozja (relatively resistant) cultivars infested with one of two hemipteran species, namely monophagous Sitobion avenae F. (grain aphid) or oligophagous Rhopalosiphum padi L. (bird cherry-oat aphid). Secondarily, aphid-elicited alternations in the antioxidative capacity towards DPPH (1,1-diphenyl-2-picrylhydrazyl) radical in insect-stressed plants were evaluated. Comprehensive comparison of expression profiles of the four sod genes showed that both insect species evoked significant upregulation of three genes sod2, sod3.4 and sod9). However, aphid infestation affected non-significant fluctuations in expression of sodB gene in seedlings of both maize genotypes. The highest levels of transcript accumulation occurred at 8 h (sod2 and sod3.4) or 24 h (sod9) post-infestation, and aphid-induced changes in the expression of sod genes were more dramatic in the Ambrozja cultivar than in the Tasty Sweet variety. Furthermore, bird cherry-oat aphid colonization had a more substantial impact on levels of DPPH radical scavenging activity in infested host seedlings than grain aphid colonization. Additionally, Ambrozja plants infested by either hemipteran species showed markedly lower antioxidative capacity compared with attacked Tasty Sweet plants.

A magical biological insecticide extracted from seeds of Millettia pachyarpa to kill cabbage aphids

NASA Astrophysics Data System (ADS)

Lin, Tianxing; Gong, Mingfu; Guan, Qinlan

2018-04-01

Millettia pachycarpa Benth is a perennial climbing shrub belonging to the genus Millettia, as it is widely used in traditional practices like agricultural pesticides, blood tonics, fish poison, and treatments for cancer and infertility. The crude extract of the seeds of M. pachycarpa had insecticidal activity on cabbage aphids. The conventional extract approach with three kinds of organic solvents: methanol, ethanol, and acetone was used for extracting of crude extract of seeds of M. pachycarpa. The leaf immersion method in a petri dish was used to measure contact activity on cabbage aphids. The field measurement method in a cabbage field was used to measure the control effect. The result indicated that the average mortality rate of cabbage aphids reached 91.3 percent under the action of crude extract of the seeds of M. pachycarpa, indicating that contacting activity against cabbage aphid was strong. After the crude extract was sprayed for 2 days, the proofread control effect of 1000 μg / mL ethanol crude extract against cabbage aphid was 85.0 percent. After 7 days of spraying, this number increased to 92.2 percent. The study concluded that crude extract of the seeds of M. pachyarpa extracted with methanol, ethanol, acetone had demonstrable contact activity against cabbage aphid and 1000 μg / mL ethanol crude extract had significant control effect against the larvae of cabbage aphid.

Pest control of aphids depends on landscape complexity and natural enemy interactions

PubMed Central

Reineking, Björn; Seo, Bumsuk; Steffan-Dewenter, Ingolf

2015-01-01

Aphids are a major concern in agricultural crops worldwide, and control by natural enemies is an essential component of the ecological intensification of agriculture. Although the complexity of agricultural landscapes is known to influence natural enemies of pests, few studies have measured the degree of pest control by different enemy guilds across gradients in landscape complexity. Here, we use multiple natural-enemy exclosures replicated in 18 fields across a gradient in landscape complexity to investigate (1) the strength of natural pest control across landscapes, measured as the difference between pest pressure in the presence and in the absence of natural enemies; (2) the differential contributions of natural enemy guilds to pest control, and the nature of their interactions across landscapes. We show that natural pest control of aphids increased up to six-fold from simple to complex landscapes. In the absence of pest control, aphid population growth was higher in complex than simple landscapes, but was reduced by natural enemies to similar growth rates across all landscapes. The effects of enemy guilds were landscape-dependent. Particularly in complex landscapes, total pest control was supplied by the combined contribution of flying insects and ground-dwellers. Birds had little overall impact on aphid control. Despite evidence for intraguild predation of flying insects by ground-dwellers and birds, the overall effect of enemy guilds on aphid control was complementary. Understanding pest control services at large spatial scales is critical to increase the success of ecological intensification schemes. Our results suggest that, where aphids are the main pest of concern, interactions between natural enemies are largely complementary and lead to a strongly positive effect of landscape complexity on pest control. Increasing the availability of seminatural habitats in agricultural landscapes may thus benefit not only natural enemies, but also the effectiveness of

Pest control of aphids depends on landscape complexity and natural enemy interactions.

PubMed

Martin, Emily A; Reineking, Björn; Seo, Bumsuk; Steffan-Dewenter, Ingolf

2015-01-01

Aphids are a major concern in agricultural crops worldwide, and control by natural enemies is an essential component of the ecological intensification of agriculture. Although the complexity of agricultural landscapes is known to influence natural enemies of pests, few studies have measured the degree of pest control by different enemy guilds across gradients in landscape complexity. Here, we use multiple natural-enemy exclosures replicated in 18 fields across a gradient in landscape complexity to investigate (1) the strength of natural pest control across landscapes, measured as the difference between pest pressure in the presence and in the absence of natural enemies; (2) the differential contributions of natural enemy guilds to pest control, and the nature of their interactions across landscapes. We show that natural pest control of aphids increased up to six-fold from simple to complex landscapes. In the absence of pest control, aphid population growth was higher in complex than simple landscapes, but was reduced by natural enemies to similar growth rates across all landscapes. The effects of enemy guilds were landscape-dependent. Particularly in complex landscapes, total pest control was supplied by the combined contribution of flying insects and ground-dwellers. Birds had little overall impact on aphid control. Despite evidence for intraguild predation of flying insects by ground-dwellers and birds, the overall effect of enemy guilds on aphid control was complementary. Understanding pest control services at large spatial scales is critical to increase the success of ecological intensification schemes. Our results suggest that, where aphids are the main pest of concern, interactions between natural enemies are largely complementary and lead to a strongly positive effect of landscape complexity on pest control. Increasing the availability of seminatural habitats in agricultural landscapes may thus benefit not only natural enemies, but also the effectiveness of

Expression differences in Aphidius ervi (Hymenoptera: Braconidae) females reared on different aphid host species

PubMed Central

Legeai, Fabrice; Gonzalez-Gonzalez, Angelica; Lavandero, Blas; Simon, Jean-Christophe

2017-01-01

The molecular mechanisms that allow generalist parasitoids to exploit many, often very distinct hosts are practically unknown. The wasp Aphidius ervi, a generalist koinobiont parasitoid of aphids, was introduced from Europe into Chile in the late 1970s to control agriculturally important aphid species. A recent study showed significant differences in host preference and host acceptance (infectivity) depending on the host A. ervi were reared on. In contrast, no genetic differentiation between A. ervi populations parasitizing different aphid species and aphids of the same species reared on different host plants was found in Chile. Additionally, the same study did not find any fitness effects in A. ervi if offspring were reared on a different host as their mothers. Here, we determined the effect of aphid host species (Sitobion avenae versus Acyrthosiphon pisum reared on two different host plants alfalfa and pea) on the transcriptome of adult A. ervi females. We found a large number of differentially expressed genes (between host species: head: 2,765; body: 1,216; within the same aphid host species reared on different host plants: alfalfa versus pea: head 593; body 222). As expected, the transcriptomes from parasitoids reared on the same host species (pea aphid) but originating from different host plants (pea versus alfalfa) were more similar to each other than the transcriptomes of parasitoids reared on a different aphid host and host plant (head: 648 and 1,524 transcripts; body: 566 and 428 transcripts). We found several differentially expressed odorant binding proteins and olfactory receptor proteins in particular, when we compared parasitoids from different host species. Additionally, we found differentially expressed genes involved in neuronal growth and development as well as signaling pathways. These results point towards a significant rewiring of the transcriptome of A. ervi depending on aphid-plant complex where parasitoids develop, even if different biotypes

A new virus from the family Tombusviridae infecting sugarcane

USDA-ARS?s Scientific Manuscript database

Sugarcane is an economically important crop cultivated in tropical and sub-tropical regions worldwide. Viral diseases are one of the major constraints for sugarcane production. Total RNA was extracted from leaves exhibiting mosaic symptoms on a sugarcane quarantine accession. A cDNA library was cons...

Short-term effects of sugarcane waste products from ethanol production plant as soil amendments on sugarcane growth and metal stabilization.

PubMed

Akkajit, Pensiri; DeSutter, Thomas; Tongcumpou, Chantra

2013-05-01

Numerous waste products have been widely studied and used as soil amendments and metal immobilizing agents. Waste utilization from ethanol production processes as soil amendments is one of the most promising and sustainable options to help utilize materials effectively, reduce waste disposal, and add value to byproducts. As a consequence, this present work carried out a four-month pot experiment of sugarcane (Saccharum officinarum L.) cultivation in Cd and Zn contaminated soil to determine the effect of three sugarcane waste products (boiler ash, filter cake and vinasse) as soil amendment on sugarcane growth, metal translocation and accumulation in sugarcane, and fractionation of Cd and Zn in soil by the BCR sequential extraction. Four treatments were tested: (1) non-amended soil; (2) 3% w/w boiler ash; (3) 3% w/w filter cake; and (4) a combination of 1.5% boiler ash and 1.5% vinasse (w/w). Our findings showed the improved biomass production of sugarcanes; 6 and 3-fold higher for the above ground parts (from 8.5 to 57.6 g per plant) and root (from 2.1 to 6.59 g per plant), respectively, as compared to non-amended soil. Although there was no significant difference in Cd and Zn uptake in sugarcane (mg kg(-1)) between the non-amended soil and the treated soils (0.44 to 0.52 mg Cd kg(-1) and 39.9 to 48.1 mg Zn kg(-1), respectively), the reduction of the most bioavailable Cd concentration (BCR1 + 2) in the treated soils (35.4-54.5%) and the transformation of metal into an insoluble fraction (BCR3) highlighted the beneficial effects of sugarcane waste-products in promoting the sugarcane growth and Cd stabilization in soil.

The ethylene response factor Pti5 contributes to potato aphid resistance in tomato independent of ethylene signalling

PubMed Central

Wu, Chengjun; Avila, Carlos A.; Goggin, Fiona L.

2015-01-01

Ethylene response factors (ERFs) comprise a large family of transcription factors that regulate numerous biological processes including growth, development, and response to environmental stresses. Here, we report that Pti5, an ERF in tomato [Solanum lycopersicum (Linnaeus)] was transcriptionally upregulated in response to the potato aphid Macrosiphum euphorbiae (Thomas), and contributed to plant defences that limited the population growth of this phloem-feeding insect. Virus-induced gene silencing of Pti5 enhanced aphid population growth on tomato, both on an aphid-susceptible cultivar and on a near-isogenic genotype that carried the Mi-1.2 resistance (R) gene. These results indicate that Pti5 contributes to basal resistance in susceptible plants and also can synergize with other R gene-mediated defences to limit aphid survival and reproduction. Although Pti5 contains the ERF motif, induction of this gene by aphids was independent of ethylene, since the ACC deaminase (ACD) transgene, which inhibits ethylene synthesis, did not diminish the responsiveness of Pti5 to aphid infestation. Furthermore, experiments with inhibitors of ethylene synthesis revealed that Pti5 and ethylene have distinctly different roles in plant responses to aphids. Whereas Pti5 contributed to antibiotic plant defences that limited aphid survival and reproduction on both resistant (Mi-1.2+) and susceptible (Mi-1.2–) genotypes, ethylene signalling promoted aphid infestation on susceptible plants but contributed to antixenotic defences that deterred the early stages of aphid host selection on resistant plants. These findings suggest that the antixenotic defences that inhibit aphid settling and the antibiotic defences that depress fecundity and promote mortality are regulated through different signalling pathways. PMID:25504643

Post-processing, energy production use of sugarcane bagasse ash

USDA-ARS?s Scientific Manuscript database

Sugarcane bagasse ash (SBA) is a multi-processed by-product produced from the milling of sugarcane. Bagasse is the fibrous material remaining after removing the sugar, water, and other impurities from the sugarcane delivered to the mill. Louisiana produces an estimated 3 million tons of bagasse each...

Shallot Aphids, Myzus ascalonicus, in Strawberry: Biocontrol Potential of Three Predators and Three Parasitoids

PubMed Central

Enkegaard, Annie; Sigsgaard, Lene; Kristensen, Kristian

2013-01-01

The parasitization capacity of 3 parasitoids and the predation capacity of 3 predators towards the shallot aphid, Myzus ascalonicus Doncaster (Homoptera: Aphididae), on strawberry, Fragaria x ananassa Duchesne (Rosales: Rosaceae) cv. Honeoye, were examined in laboratory experiments. In Petri dish assays, both Aphidius colemani Viereck (Hymenoptera: Aphidiidae) and A. ervi Haliday readily stung shallot aphids, with no significant difference in stinging frequency between the two species. A. ervi induced a significantly higher mortality (79.0 ± 7.2%) in terms of stung aphids compared with A. colemani (55.3 ± 4.1%); however, only a minor fraction (2.7 ± 1.8% and 7.1 ± 3.1%, respectively) of the killed aphids resulted in formation of mummies, presumably due to a physiological response to parasitism. The low percentage of mummification precludes the use of either Aphidius species in anything but inundative biocontrol. In similar set-ups, Aphelinus abdominalis (Dalman) (Hymenoptera: Aphelinidae) killed almost half (49.6 ± 5.3%) of the exposed aphids through host feeding. In addition, 23.2 ± 7.3% of non-host-fed aphids developed into mummified aphids, and 38.1 ± 13.2% of non-host-fed aphids died from other parasitoid-induced causes. However, the host feeding rate was reduced to only 1.2 ± 0.8%, and no significant parasitization mortality was observed on strawberry plants, suggesting that host plants interfered with A. abdominalis activity. This parasitoid does not, therefore, seem to be suited to either inoculative or inundative biocontrol of shallot aphids in strawberry. The three predators studied were the green lacewing, Chrysoperla carnea Steph. (Neuroptera: Chrysopidae), the two-spotted lady beetle, Adalia bipunctata L. (Coleoptera: Coccinellidae), and the gall midge Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae). Third instars of all 3 predators readily preyed upon the shallot aphid in Petri dish set-ups with significant differences in daily

Key Transport and Ammonia Recycling Genes Involved in Aphid Symbiosis Respond to Host-Plant Specialization.

PubMed

Kim, Dohyup; Minhas, Bushra F; Li-Byarlay, Hongmei; Hansen, Allison K

2018-05-25

Microbes are known to influence insect-plant interactions; however, it is unclear if host-plant diet influences the regulation of nutritional insect symbioses. The pea aphid, Acyrthosiphon pisum , requires its nutritional endosymbiont, Buchnera , for the production of essential amino acids. We hypothesize that key aphid genes that regulate the nutritional symbioses respond to host-plant diet when aphids feed on a specialized (alfalfa) compared to a universal host-plant diet (fava), which vary in amino acid profiles. Using RNA-Seq and whole genome bisulfite sequencing, we measured gene expression and DNA methylation profiles for such genes when aphids fed on either their specialized or universal host-plant diets. Our results reveal that when aphids feed on their specialized host-plant they significantly up-regulate and/or hypo-methylate key aphid genes in bacteriocytes related to the amino acid metabolism, including glutamine synthetase in the GOGAT cycle that recycles ammonia into glutamine and the glutamine transporter ApGLNT1 Moreover, regardless of what host-plant aphids feed on we observed significant up-regulation and differential methylation of key genes involved in the amino acid metabolism and the glycine/serine metabolism, a metabolic program observed in proliferating cancer cells potentially to combat oxidative stress. Based on our results, we suggest that this regulatory response of key symbiosis genes in bacteriocytes allows aphids to feed on a suboptimal host-plant that they specialize on. Copyright © 2018, G3: Genes, Genomes, Genetics.

Agronomy of strip intercropping broccoli with alyssum for biological control of aphids

USDA-ARS?s Scientific Manuscript database

Organic broccoli growers in California typically control aphids by intercropping broccoli with strips of alyssum (Lobularia maritima (L.) Desv.) which attracts hoverflies (Diptera: Syrphidae) that are important predators of aphids. A three year study with transplanted organic broccoli in Salinas, ...

First report of Pandora neoaphidis resting spore formation in vivo in aphid hosts under field conditions

USDA-ARS?s Scientific Manuscript database

The entomopathogenic fungus PANDORA NEOAPHIDIS is a recognized pathogen of aphids, causing natural epizootics in aphid populations, and interacts favorably with aphid predators and parasitoids. Survival of entomophthoralean fungi in periods of unsuitable weather conditions or lack of appropriate hos...

GGE analysis of ratooning ability in Louisiana sugarcane breeding

USDA-ARS?s Scientific Manuscript database

Ratooning ability is an important sugarcane growth habit that affects profitability. Ratooning ability is the ability of sugarcane to regrow after harvesting and it is measured in this research as the percentage of second ratoon of a trait to plant cane. In sugarcane breeding programs, it is time co...

Post-processing, energy production use of sugarcane bagasse ash

USDA-ARS?s Scientific Manuscript database

Sugarcane bagasse ash (SBA) is a multi-process by-product produced from the milling of sugarcane. Bagasse is the fibrous material remaining after removing the sugar, water, and other impurities from the sugarcane delivered to the mill. Louisiana produces an estimated 2.7 mt of bagasse each year. In ...

Selection of embryogenic sugarcane callus by image analysis.

PubMed

Honda, H; Ito, T; Yamada, J; Hanai, T; Matsuoka, M; Kobayashi, T

1999-01-01

In the cultivation of plant calli on solid media, two kinds of calli such as compact and friable calli, which are a bright yellow and a whitish clump, respectively, are often obtained. Distinction of these calli is of much importance in the regeneration step. The image analysis system associated with a Charge Coupled Device (CCD) camera and microscopy were used to distinguish sugarcane calli. The original images from compact and friable calli were input to a computer via an image analysis board. At first, the brightnesses of trichromatic colors, red (R), green (G) and blue (B), of each pixels were extracted and the average brightness value for each color was calculated. From these values of the trichromatic colors, compact and friable calli could not be clearly distinguished. Next, the brightness of yellow, Br(Y), and white, Br(W), were defined using Br(R), Br(G) and Br(B), and the difference between Br(Y) and Br(W), Br(Y-W), which can be used to express the yellowish grade, was calculated. When Br(Y-W) was determined from all pixels of the original images of both calli, the compact calli were found to be clearly distinguished from the friable calli by the frequency distributions of Br(Y-W). Average brightness center value, Av(C(Y-W)), was calculated from the frequency distributions. It was found that the calli with less than 10 units of Av(C(Y-W)) was never regenerated and a proportional relationship between Av(C(Y-W)) and the regeneration frequency of the callus line was obtained.

Redox Control of Aphid Resistance through Altered Cell Wall Composition and Nutritional Quality1[OPEN

PubMed Central

Rasool, Brwa; Marcus, Sue E.

2017-01-01

The mechanisms underpinning plant perception of phloem-feeding insects, particularly aphids, remain poorly characterized. Therefore, the role of apoplastic redox state in controlling aphid infestation was explored using transgenic tobacco (Nicotiana tabacum) plants that have either high (PAO) or low (TAO) ascorbate oxidase (AO) activities relative to the wild type. Only a small number of leaf transcripts and metabolites were changed in response to genotype, and cell wall composition was largely unaffected. Aphid fecundity was decreased significantly in TAO plants compared with other lines. Leaf sugar levels were increased and maximum extractable AO activities were decreased in response to aphids in all genotypes. Transcripts encoding the Respiratory Burst Oxidase Homolog F, signaling components involved in ethylene and other hormone-mediated pathways, photosynthetic electron transport components, sugar, amino acid, and cell wall metabolism, were increased significantly in the TAO plants in response to aphid perception relative to other lines. The levels of galactosylated xyloglucan were decreased significantly in response to aphid feeding in all the lines, the effect being the least in the TAO plants. Similarly, all lines exhibited increases in tightly bound (1→4)-β-galactan. Taken together, these findings identify AO-dependent mechanisms that limit aphid infestation. PMID:28743764

Extraordinary proliferation of microorganisms in aposymbiotic pea aphids, Acyrthosiphon pisum.

PubMed

Nakabachi, Atsushi; Ishikawa, Hajime; Kudo, Toshiaki

2003-03-01

Aposymbiotic pea aphids, which were deprived of their intracellular symbiotic bacterium, Buchnera, exhibit growth retardation and no fecundity. High performance liquid chromatographic (HPLC) analysis revealed that these aposymbiotic aphids, when reared on broad bean plants, accumulated a large amount of histamine. To assess the possibility of extraordinary proliferation of microorganisms other than Buchnera, we enumerated eubacteria and fungi in aphids using the real-time quantitative PCR method that targets genes encoding small-subunit rRNAs. The result showed that these microorganisms were extremely abundant in the aposymbiotic aphids reared on plants. Microbial communities in aposymbiotic aphids were further profiled by phylogenetic analysis of small-subunit rDNAs. Of 172 nonchimeric sequences of fungal 18S rDNAs, 138 (80.2%) belonged to the phylum Ascomycota. Among them, 21 clustered within a monophyletic group consisting of insect-pathogenic fungi and yeast-like symbionts of homopteran insects. Thirty-one (18.0%), two (1.2%), and one (0.6%) clones were clustered within the Basidiomycota, Zygomycota, and Oomycota, respectively. Of 167 nonchimeric sequences of eubacterial 16S rDNAs, 84 (50.3%) belonged to the gamma-subdivision of Proteobacteria to which most primary endosymbionts of insects and prolific histamine producers belong. Forty (24.0%), 25 (15.0%), 10 (6.0%), and five (3.0%) clones were clustered within alpha-Proteobacteria, Cytophaga-Flavobacterium-Bacteroides (CFB) group, Actinobacteria, and beta-Proteobacteria, respectively. Three had no phylogenetic association with known taxonomic divisions. None of the sequences studied in this study coincided exactly with those deposited in GenBank.

Sugarcane and other crops as fuel feedstocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Irvine, J.E.

1980-07-01

The use of sugarcane as a feedstock for fuel alcohol production in Brazil, and in Zimbabwe Rhodesia and Panama stimulated tremendous interest in the potential of agricultural crops for renewable energy sources. The cost of the feedstock is important. Corn, the current major agricultural feedstock in US fuel alcohol production, costs 60 to 80% of the selling price of the alcohol produced from it. Production costs for sugarcane and sugarbeets are higher than for corn. Sugarcane and sugarbeets, yield more fermentable carbohydrates per acre than any other crop. Sugarcane has the distinct advantage of containing a large amount of fibermore » in the harvested portion. The feedstock cost of sugarcane can be reduced by producing more cane per acre. Sweet sorghum has been discussed as a fuel crop. Cassana, the tapioca source, is thought to be a fuel crop of major potential. Feedstock cost can also be reduced through management decisions that reduce costly practices. Cultivation and fertilizer costs can be reduced. The operating cost of the processing plant is affected by the choice of crops grown for feedstock, both by their cost and by availability. (DP)« less

Clarification Properties of Trash and Stalk Tissues from Sugarcane

USDA-ARS?s Scientific Manuscript database

The effect of the U.S. and world-wide change from burnt to unburnt (green) sugarcane harvesting on processing, and the use of sugarcane leaves and tops as a biomass source has not been fully characterized. Sugarcane whole-stalks were harvested from the first ratoon crop of five commercial, Louisian...

2G ethanol from the whole sugarcane lignocellulosic biomass.

PubMed

Pereira, Sandra Cerqueira; Maehara, Larissa; Machado, Cristina Maria Monteiro; Farinas, Cristiane Sanchez

2015-01-01

In the sugarcane industry, large amounts of lignocellulosic residues are generated, which includes bagasse, straw, and tops. The use of the whole sugarcane lignocellulosic biomass for the production of second-generation (2G) ethanol can be a potential alternative to contribute to the economic viability of this process. Here, we conducted a systematic comparative study of the use of the lignocellulosic residues from the whole sugarcane lignocellulosic biomass (bagasse, straw, and tops) from commercial sugarcane varieties for the production of 2G ethanol. In addition, the feasibility of using a mixture of these residues from a selected variety was also investigated. The materials were pretreated with dilute acid and hydrolyzed with a commercial enzymatic preparation, after which the hydrolysates were fermented using an industrial strain of Saccharomyces cerevisiae. The susceptibility to enzymatic saccharification was higher for the tops, followed by straw and bagasse. Interestingly, the fermentability of the hydrolysates showed a different profile, with straw achieving the highest ethanol yields, followed by tops and bagasse. Using a mixture of the different sugarcane parts (bagasse-straw-tops, 1:1:1, in a dry-weight basis), it was possible to achieve a 55% higher enzymatic conversion and a 25% higher ethanol yield, compared to use of the bagasse alone. For the four commercial sugarcane varieties evaluated using the same experimental set of conditions, it was found that the variety of sugarcane was not a significant factor in the 2G ethanol production process. Assessment of use of the whole lignocellulosic sugarcane biomass clearly showed that 2G ethanol production could be significantly improved by the combined use of bagasse, straw, and tops, when compared to the use of bagasse alone. The lower susceptibility to saccharification of sugarcane bagasse, as well as the lower fermentability of its hydrolysates, can be compensated by using it in combination with straw

Plant Species Loss Affects Life-History Traits of Aphids and Their Parasitoids

PubMed Central

Petermann, Jana S.; Roscher, Christiane; Weigelt, Alexandra; Weisser, Wolfgang W.; Schmid, Bernhard

2010-01-01

The consequences of plant species loss are rarely assessed in a multi-trophic context and especially effects on life-history traits of organisms at higher trophic levels have remained largely unstudied. We used a grassland biodiversity experiment and measured the effects of two components of plant diversity, plant species richness and the presence of nitrogen-fixing legumes, on several life-history traits of naturally colonizing aphids and their primary and secondary parasitoids in the field. We found that, irrespective of aphid species identity, the proportion of winged aphid morphs decreased with increasing plant species richness, which was correlated with decreasing host plant biomass. Similarly, emergence proportions of parasitoids decreased with increasing plant species richness. Both, emergence proportions and proportions of female parasitoids were lower in plots with legumes, where host plants had increased nitrogen concentrations. This effect of legume presence could indicate that aphids were better defended against parasitoids in high-nitrogen environments. Body mass of emerged individuals of the two most abundant primary parasitoid species was, however, higher in plots with legumes, suggesting that once parasitoids could overcome aphid defenses, they could profit from larger or more nutritious hosts. Our study demonstrates that cascading effects of plant species loss on higher trophic levels such as aphids, parasitoids and secondary parasitoids begin with changed life-history traits of these insects. Thus, life-history traits of organisms at higher trophic levels may be useful indicators of bottom-up effects of plant diversity on the biodiversity of consumers. PMID:20700511

Solanum nigrescens, a problematic nightshade species in Louisiana sugarcane

USDA-ARS?s Scientific Manuscript database

A large perennial broadleaf weed appearing to be a member of the Solanum genus was observed in a commercial sugarcane (Saccharum spp.) field in Vacherie, LA in 2010. Since then, this weed has spread to sugarcane fields in 17 of the 24 parishes which produce sugarcane. The weed has been identified as...

Rise and fall of cotton aphid (Hemiptera: Aphididae) populations in southeastern cotton production systems.

PubMed

Abney, Mark R; Ruberson, John R; Herzog, Gary A; Kring, Timothy J; Steinkraus, Donald C; Roberts, Phillip M

2008-02-01

The impact of natural enemies on cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), populations in cotton, Gossypium hirsutum L., production systems in the southeastern United States was evaluated over 3 yr in irrigated commercial cotton fields. Fungal epizootics caused by the entomopathogen Neozygites fresenii (Nowakowski) Batko reduced aphid numbers to subthreshold levels in 1999, 2000, and 2001 and occurred consistently in early to mid-July in all 3 yr. Scymnus spp. were the most abundant aphidophagous predators, although other coccinellid species and generalist predators such as spiders, fire ants, heteropterans, and neuropterans also were present. Studies using arthropod exclusion cages demonstrated little impact of predators or parasitoids on aphid populations before fungal epizootics. Arthropod natural enemies were most abundant after epizootics and may have suppressed aphid populations late in the season. Seed cotton yield, and lint quality were not affected by aphicide applications in any year of the study. Implications of these findings for aphid management in the southeastern United States are discussed.

Foliar aphid feeding recruits rhizosphere bacteria and primes plant immunity against pathogenic and non-pathogenic bacteria in pepper.

PubMed

Lee, Boyoung; Lee, Soohyun; Ryu, Choong-Min

2012-07-01

Plants modulate defence signalling networks in response to different biotic stresses. The present study evaluated the effect of a phloem-sucking aphid on plant defence mechanisms in pepper (Capsicum annuum) during subsequent pathogen attacks on leaves and rhizosphere bacteria on roots. Plants were pretreated with aphids and/or the chemical trigger benzothiadiazol (BTH) 7 d before being challenged with two pathogenic bacteria, Xanthomonas axonopodis pv. vesicatoria (Xav) as a compatible pathogen and X. axonopodis pv. glycines (Xag) as an incompatible (non-host) pathogen. Disease severity was noticeably lower in aphid- and BTH + aphid-treated plants than in controls. Although treatment with BTH or aphids alone did not affect the hypersensitive response (HR) against Xag strain 8ra, the combination treatment had a synergistic effect on the HR. The aphid population was reduced by BTH pretreatment and by combination treatment with BTH and bacterial pathogens in a synergistic manner. Analysis of the expression of the defence-related genes Capsicum annum pathogenesis-related gene 9 (CaPR9), chitinase 2 (CaCHI2), SAR8·2 and Lipoxygenase1 (CaLOX1) revealed that aphid infestation resulted in the priming of the systemic defence responses against compatible and incompatible pathogens. Conversely, pre-challenge with the compatible pathogen Xav on pepper leaves significantly reduced aphid numbers. Aphid infestation increased the population of the beneficial Bacillus subtilis GB03 but reduced that of the pathogenic Ralstonia solanacearum SL1931. The expression of defence-related genes in the root and leaf after aphid feeding indicated that the above-ground aphid infestation elicited salicylic acid and jasmonic acid signalling throughout the whole plant. The findings of this study show that aphid feeding elicits plant resistance responses and attracts beneficial bacterial populations to help the plant cope with subsequent pathogen attacks.

Foliar aphid feeding recruits rhizosphere bacteria and primes plant immunity against pathogenic and non-pathogenic bacteria in pepper

PubMed Central

Lee, Boyoung; Lee, Soohyun; Ryu, Choong-Min

2012-01-01

Background and Aims Plants modulate defence signalling networks in response to different biotic stresses. The present study evaluated the effect of a phloem-sucking aphid on plant defence mechanisms in pepper (Capsicum annuum) during subsequent pathogen attacks on leaves and rhizosphere bacteria on roots. Methods Plants were pretreated with aphids and/or the chemical trigger benzothiadiazol (BTH) 7 d before being challenged with two pathogenic bacteria, Xanthomonas axonopodis pv. vesicatoria (Xav) as a compatible pathogen and X. axonopodis pv. glycines (Xag) as an incompatible (non-host) pathogen. Key Results Disease severity was noticeably lower in aphid- and BTH + aphid-treated plants than in controls. Although treatment with BTH or aphids alone did not affect the hypersensitive response (HR) against Xag strain 8ra, the combination treatment had a synergistic effect on the HR. The aphid population was reduced by BTH pretreatment and by combination treatment with BTH and bacterial pathogens in a synergistic manner. Analysis of the expression of the defence-related genes Capsicum annum pathogenesis-related gene 9 (CaPR9), chitinase 2 (CaCHI2), SAR8·2 and Lipoxygenase1 (CaLOX1) revealed that aphid infestation resulted in the priming of the systemic defence responses against compatible and incompatible pathogens. Conversely, pre-challenge with the compatible pathogen Xav on pepper leaves significantly reduced aphid numbers. Aphid infestation increased the population of the beneficial Bacillus subtilis GB03 but reduced that of the pathogenic Ralstonia solanacearum SL1931. The expression of defence-related genes in the root and leaf after aphid feeding indicated that the above-ground aphid infestation elicited salicylic acid and jasmonic acid signalling throughout the whole plant. Conclusions The findings of this study show that aphid feeding elicits plant resistance responses and attracts beneficial bacterial populations to help the plant cope with subsequent

Distribution and diversity of Russian wheat aphid (Hemiptera: Aphididae) biotypes in South Africa and Lesotho.

PubMed

Jankielsohn, Astrid

2011-10-01

Russian wheat aphid, Diuraphis noxia (Kurdjumov) (Hemiptera: Aphididae) was recorded for the first time in South Africa in 1978. In 2005, a second biotype, RWASA2, emerged, and here we report on the emergence of yet another biotype, found for the first time in 2009. The discovery of new Russian wheat aphid biotypes is a significant challenge to the wheat, Triticum aestivum L., industry in South Africa. Russian wheat aphid resistance in wheat, that offered wheat producers a long-term solution to Russian wheat aphid control, may no longer be effective in areas where the new biotypes occur. It is therefore critical to determine the diversity and extent of distribution of biotypes in South Africa to successfully deploy Russian wheat aphid resistance in wheat. Screening of 96 Russian wheat aphid clones resulted in identification of three Russian wheat aphid biotypes. Infestations of RWASA1 caused susceptible damage symptoms only in wheat entries containing the Dn3 gene. Infestations of RWASA2 caused susceptible damage symptoms in wheat entries containing Dn1, Dn2, Dn3, and Dn9 resistant genes. Based on the damage-rating scores for the seven resistance sources, a new biotype, which caused damage rating scores different from those for RWASA1 and RWASA2, was evident among the Russian wheat aphid populations tested. This new biotype is virulent to the same resistance sources as RWASA2 (Dn1, Dn2, Dn3, and Dn9), but it also has added virulence to Dn4, whereas RWASA2 is avirulent to this resistance source.

Rational regional distribution of sugarcane cultivars in China

PubMed Central

Luo, Jun; Pan, Yong-Bao; Xu, Liping; Grisham, Michael Paul; Zhang, Hua; Que, Youxiong

2015-01-01

Knowing yield potential and yield stability of sugarcane cultivars is of significance in guiding sugarcane breeding and rationalising regional distribution of sugarcane cultivars. In the present study, a heritability-adjusted genotype main effect plus genotype × environment (HA-GGE) biplot program was used to analyze the cane and sucrose yields of 44 newly released sugarcane cultivars at eight pilot test sites. The cane and sucrose yields of nine cultivars were higher than those of the control cultivar ROC22. From the perspective of cane yield, cultivars FN 40 and YZ 06–407 were well adapted to a wider range of conditions and produced relatively high cane yields in several pilot sites. From the perspective of sucrose yield, cultivars LC 03–1137, FN 38, FN 41, MT 01–77 and LC 05–136 were well adapted to a wide range of conditions and produced relatively high sucrose yields. Based on these results, three high yielding and widely adapted cultivars, namely, FN 39, LC 05–136, and YZ 05–51 were recommended for production in three major Chinese sugarcane planting areas. The results will provide a theoretical basis for recommending the effective use and rational regional distribution of sugarcane cultivars in China. PMID:26499905

Unravelling mycorrhiza-induced wheat susceptibility to the English grain aphid Sitobion avenae

PubMed Central

Simon, Amma L.; Wellham, Peter A. D.; Aradottir, Gudbjorg I.; Gange, Alan C.

2017-01-01

Arbuscular mycorrhizal (AM) fungi are root symbionts that can increase or decrease aphid growth rates and reproduction, but the reason by which this happens is unknown. To investigate the underlying mechanisms of this interaction, we examined the effect of AM fungi on the English Grain aphid (Sitobion avenae) development, reproduction, attraction, settlement and feeding behaviour on two naturally susceptible varieties Triticum aestivum (L.) variety Solstice and T. monococcum MDR037, and two naturally resistant lines, T. monococcum MDR045 and MDR049. Mycorrhizal colonisation increased the attractiveness of T. aestivum var. Solstice to aphids, but there was no effect on aphid development on this variety. Using the Electrical Penetration Graph (EPG) technique, we found that mycorrhizal colonisation increased aphid phloem feeding on T. monococcum MDR037 and MDR045, colonisation also increased growth rate and reproductive success of S. avenae on these varieties. Mycorrhizas increased vascular bundle size, demonstrating that these fungi can influence plant anatomy. We discuss if and how this could be related to an enhanced success rate in phloem feeding in two varieties. Overall, we present and discuss how mycorrhizal fungi can affect the feeding behaviour of S. avenae in wheat, inducing susceptibility in a resistant variety. PMID:28406246

Sublethal and hormesis effects of imidacloprid on the soybean aphid Aphis glycines.

PubMed

Qu, Yanyan; Xiao, Da; Li, Jinyu; Chen, Zhou; Biondi, Antonio; Desneux, Nicolas; Gao, Xiwu; Song, Dunlun

2015-04-01

The soybean aphid, Aphis glycines Matsumura, is a major pest in soybean crop. Current management of this pest relies mainly on insecticides applications, and the neonicotinoid imidacloprid has been proposed as an effective insecticide to control A. glycines in soybean field. Imidacloprid at lethal concentrations not only exerts acute toxicity to A. glycines, but also cause various biological changes when aphids are chronically exposed to lower concentrations. In this study, we assessed the effects of a low-lethal (0.20 mg L(-1)) and two sublethal (0.05 and 0.10 mg L(-1)) imidacloprid concentrations on various A. glycines life history traits. Aphid exposure to 0.20 mg L(-1) imidacloprid caused slower juvenile development, shorter reproductive period, and reduced adult longevity, fecundity and total lifespan. Stimulatory effects, i.e. hormesis, on reproduction and immature development duration were observed in aphids exposed to the lower sublethal imidacloprid concentrations. Consequently, the net reproduction rate (R 0) was significantly higher than in the control aphids. These findings stress the importance of the actual imidacloprid concentration in its toxicological properties on A. glycines. Therefore, our results would be useful for assessing the overall effects of imidacloprid on A. glycines and for optimizing integrated pest management programs targeting this pest.

Unravelling mycorrhiza-induced wheat susceptibility to the English grain aphid Sitobion avenae

NASA Astrophysics Data System (ADS)

Simon, Amma L.; Wellham, Peter A. D.; Aradottir, Gudbjorg I.; Gange, Alan C.

2017-04-01

Arbuscular mycorrhizal (AM) fungi are root symbionts that can increase or decrease aphid growth rates and reproduction, but the reason by which this happens is unknown. To investigate the underlying mechanisms of this interaction, we examined the effect of AM fungi on the English Grain aphid (Sitobion avenae) development, reproduction, attraction, settlement and feeding behaviour on two naturally susceptible varieties Triticum aestivum (L.) variety Solstice and T. monococcum MDR037, and two naturally resistant lines, T. monococcum MDR045 and MDR049. Mycorrhizal colonisation increased the attractiveness of T. aestivum var. Solstice to aphids, but there was no effect on aphid development on this variety. Using the Electrical Penetration Graph (EPG) technique, we found that mycorrhizal colonisation increased aphid phloem feeding on T. monococcum MDR037 and MDR045, colonisation also increased growth rate and reproductive success of S. avenae on these varieties. Mycorrhizas increased vascular bundle size, demonstrating that these fungi can influence plant anatomy. We discuss if and how this could be related to an enhanced success rate in phloem feeding in two varieties. Overall, we present and discuss how mycorrhizal fungi can affect the feeding behaviour of S. avenae in wheat, inducing susceptibility in a resistant variety.

Unrelated facultative endosymbionts protect aphids against a fungal pathogen.

PubMed

Łukasik, Piotr; van Asch, Margriet; Guo, Huifang; Ferrari, Julia; Godfray, H Charles J

2013-02-01

The importance of microbial facultative endosymbionts to insects is increasingly being recognized, but our understanding of how the fitness effects of infection are distributed across symbiont taxa is limited. In the pea aphid, some of the seven known species of facultative symbionts influence their host's resistance to natural enemies, including parasitoid wasps and a pathogenic fungus. Here we show that protection against this entomopathogen, Pandora neoaphidis, can be conferred by strains of four distantly related symbionts (in the genera Regiella, Rickettsia, Rickettsiella and Spiroplasma). They reduce mortality and also decrease fungal sporulation on dead aphids which may help protect nearby genetically identical insects. Pea aphids thus obtain protection from natural enemies through association with a wider range of microbial associates than has previously been thought. Providing resistance against natural enemies appears to be a particularly common way for facultative endosymbionts to increase in frequency within host populations. © 2012 Blackwell Publishing Ltd/CNRS.

Herbicide options for suppressing bermudagrass in sugarcane

USDA-ARS?s Scientific Manuscript database

Bermudagrass is a problematic weed in Louisiana sugarcane. The most effective herbicide options are limited to the fallow period prior to planting. Frequently, efforts to eliminate bermudagrass from fields during the fallow season are unsuccessful. This subjects newly planted sugarcane to competitio...

Identification of differentially expressed genes related to aphid resistance in cucumber (Cucumis sativus L.)

PubMed Central

Liang, Danna; Liu, Min; Hu, Qijing; He, Min; Qi, Xiaohua; Xu, Qiang; Zhou, Fucai; Chen, Xuehao

2015-01-01

Cucumber, a very important vegetable crop worldwide, is easily damaged by pests. Aphids (Aphis gossypii Glover) are among the most serious pests in cucumber production and often cause severe loss of yield and make fruit quality get worse. Identifying genes that render cucumbers resistant to aphid-induced damage and breeding aphid-resistant cucumber varieties have become the most promising control strategies. In this study, a Illumina Genome Analyzer platform was applied to monitor changes in gene expression in the whole genome of the cucumber cultivar ‘EP6392’ which is resistant to aphids. Nine DGE libraries were constructed from infected and uninfected leaves. In total, 49 differentially expressed genes related to cucumber aphid resistance were screened during the treatment period. These genes are mainly associated with signal transduction, plant-pathogen interactions, flavonoid biosynthesis, amino acid metabolism and sugar metabolism pathways. Eight of the 49 genes may be associated with aphid resistance. Finally, expression of 9 randomly selected genes was evaluated by qRT-PCR to verify the results for the tag-mapped genes. With the exception of 1-aminocyclopropane-1-carboxylate oxidase homolog 6, the expression of the chosen genes was in agreement with the results of the tag-sequencing analysis patterns. PMID:25959296

Preceding crop affects soybean aphid abundance and predator-prey dynamics in soybean

USDA-ARS?s Scientific Manuscript database

Crop rotations alter the soil environment and physiology of the subsequent crop in ways that may affect herbivore abundance. Soybean aphids are a consistent pest of soybean throughout North America, but little work has focused on how preceding crops may affect aphid populations. In a replicated expe...

AtWRKY22 promotes susceptibility to aphids and modulates salicylic acid and jasmonic acid signalling

PubMed Central

Kloth, Karen J.; Wiegers, Gerrie L.; Busscher-Lange, Jacqueline; van Haarst, Jan C.; Kruijer, Willem; Bouwmeester, Harro J.; Dicke, Marcel; Jongsma, Maarten A.

2016-01-01

Aphids induce many transcriptional perturbations in their host plants, but the signalling cascades responsible and the effects on plant resistance are largely unknown. Through a genome-wide association (GWA) mapping study in Arabidopsis thaliana, we identified WRKY22 as a candidate gene associated with feeding behaviour of the green peach aphid, Myzus persicae. The transcription factor WRKY22 is known to be involved in pathogen-triggered immunity, and WRKY22 gene expression has been shown to be induced by aphids. Assessment of aphid population development and feeding behaviour on knockout mutants and overexpression lines showed that WRKY22 increases susceptibility to M. persicae via a mesophyll-located mechanism. mRNA sequencing analysis of aphid-infested wrky22 knockout plants revealed the up-regulation of genes involved in salicylic acid (SA) signalling and down-regulation of genes involved in plant growth and cell-wall loosening. In addition, mechanostimulation of knockout plants by clip cages up-regulated jasmonic acid (JA)-responsive genes, resulting in substantial negative JA–SA crosstalk. Based on this and previous studies, WRKY22 is considered to modulate the interplay between the SA and JA pathways in response to a wide range of biotic and abiotic stimuli. Its induction by aphids and its role in suppressing SA and JA signalling make WRKY22 a potential target for aphids to manipulate host plant defences. PMID:27107291

Transcriptomic and proteomic analyses of seasonal photoperiodism in the pea aphid

PubMed Central

Le Trionnaire, G; Francis, F; Jaubert-Possamai, S; Bonhomme, J; De Pauw, E; Gauthier, J-P; Haubruge, E; Legeai, F; Prunier-Leterme, N; Simon, J-C; Tanguy, S; Tagu, D

2009-01-01

Background Aphid adaptation to harsh winter conditions is illustrated by an alternation of their reproductive mode. Aphids detect photoperiod shortening by sensing the length of the night and switch from viviparous parthenogenesis in spring and summer, to oviparous sexual reproduction in autumn. The photoperiodic signal is transduced from the head to the reproductive tract to change the fate of the future oocytes from mitotic diploid embryogenesis to haploid formation of gametes. This process takes place in three consecutive generations due to viviparous parthenogenesis. To understand the molecular basis of the switch in the reproductive mode, transcriptomic and proteomic approaches were used to detect significantly regulated transcripts and polypeptides in the heads of the pea aphid Acyrthosiphon pisum. Results The transcriptomic profiles of the heads of the first generation were slightly affected by photoperiod shortening. This suggests that trans-generation signalling between the grand-mothers and the viviparous embryos they contain is not essential. By analogy, many of the genes and some of the proteins regulated in the heads of the second generation are implicated in visual functions, photoreception and cuticle structure. The modification of the cuticle could be accompanied by a down-regulation of the N-β-alanyldopamine pathway and desclerotization. In Drosophila, modification of the insulin pathway could cause a decrease of juvenile hormones in short-day reared aphids. Conclusion This work led to the construction of hypotheses for photoperiodic regulation of the switch of the reproductive mode in aphids. PMID:19788735

Gene expression profiles responses to aphid feeding in chrysanthemum (Chrysanthemum morifolium).

PubMed

Xia, Xiaolong; Shao, Yafeng; Jiang, Jiafu; Ren, Liping; Chen, Fadi; Fang, Weimin; Guan, Zhiyong; Chen, Sumei

2014-12-02

Chrysanthemum is an important ornamental plant all over the world. It is easily attacked by aphid, Macrosiphoniella sanbourni. The molecular mechanisms of plant defense responses to aphid are only partially understood. Here, we investigate the gene expression changes in response to aphid feeding in chrysanthemum leaf by RNA-Seq technology. Three libraries were generated from pooled leaf tissues of Chrysanthemum morifolium 'nannongxunzhang' that were collected at different time points with (Y) or without (CK) aphid infestations and mock puncture treatment (Z), and sequenced using an Illumina HiSeqTM 2000 platform. A total of 7,363,292, 7,215,860 and 7,319,841 clean reads were obtained in library CK, Y and Z, respectively. The proportion of clean reads was >97.29% in each library. Approximately 76.35% of the clean reads were mapped to a reference gene database including all known chrysanthemum unigene sequences. 1,157, 527 and 340 differentially expressed genes (DEGs) were identified in the comparison of CK-VS-Y, CK-VS-Z and Z-VS-Y, respectively. These DEGs were involved in phytohormone signaling, cell wall biosynthesis, photosynthesis, reactive oxygen species (ROS) pathway and transcription factor regulatory networks, and so on. Changes in gene expression induced by aphid feeding are shown to be multifaceted. There are various forms of crosstalk between different pathways those genes belonging to, which would allow plants to fine-tune its defense responses.

Aphid salivary proteases are capable of degrading sieve-tube proteins.

PubMed

Furch, Alexandra C U; van Bel, Aart J E; Will, Torsten

2015-02-01

Sieve tubes serve as transport conduits for photo-assimilates and other resources in angiosperms and are profitable targets for piercing-sucking insects such as aphids. Sieve-tube sap also contains significant amounts of proteins with diverse functions, for example in signalling, metabolism, and defence. The identification of salivary proteases in Acyrthosiphon pisum led to the hypothesis that aphids might be able to digest these proteins and by doing so suppress plant defence and access additional nitrogen sources. Here, the scarce knowledge of proteases in aphid saliva is briefly reviewed. In order to provide a better platform for discussion, we conducted a few tests on in vitro protease activity and degradation of sieve-tube sap proteins of Cucurbita maxima by watery saliva. Inhibition of protein degradation by EDTA indicates the presence of different types of proteases (e.g. metalloproteses) in saliva of A. pisum. Proteases in the watery saliva from Macrosiphum euphorbiae and A. pisum were able to degrade the most abundant phloem protein, which is phloem protein 1. Our results provide support for the breakdown of sieve-element proteins by aphid saliva in order to suppress/neutralize the defence responses of the plant and to make proteins of sieve-tube sap accessible as a nitrogen source, as is discussed in detail. Finally, we discuss whether glycosylation of sieve-element proteins and the presence of protease inhibitors may confer partial protection against the proteolytic activity of aphid saliva. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Trophic transfer of soil arsenate and associated toxic effects in a plant-aphid-parasitoid system

NASA Astrophysics Data System (ADS)

Lee, Y. S.; Wee, J.; Lee, M.; Hong, J.; Cho, K.

2017-12-01

Terrestrial toxic effects of soil arsenic were studied using a model system consisting of soil which artificially treated with arsenic, Capsicum annum,Myzus persicae and Aphidus colemani. We investigated the transfer of arsenic in a soil-plant-aphid system and toxic effect of elevated arsenic through a plant-aphid-parasitoid system. To remove the effect of poor plant growth on aphid performance, test concentrations which have a no effect on health plant growth were selected. Arsenic concentration of growth medium, plant tissues (root, stem, leaf) aphids were measured to observe the arsenic transfer. Correlation matrix was made with arsenic in growth medium which extracted with three extractants (aquaregia, 0.01 M CaCl2 and deionized water), arsenic in plant tissues and plant performance. Toxic effects of elevated arsenic concentrations on each species were investigated at population level. Studied plant performances were dry weight of each tissue, elongation of roots and stems, area of leaves, chlorophyll content of leaves, protein content of leaves and sugar content of leaves. Mean development time, fecundity and honeydew excretion of the aphids and host choice capacity and parasitism success of the parasitoids were examined. In addition, enzyme activities of the plants and the aphids against reactive oxygen species (ROS) induced by arsenic stress were also investigated. The results suggest that arsenic concentration in plant tissues and aphids were elevated with increased concentration of arsenic in soil. Decreased fecundity and honeydew excretion of aphids were observed and decreased eclosion rate of parasitoids were observed with increased arsenic treatment in growth medium. The results showed low concentration of arsenic in soil can transfer through food chain and can impact on higher trophic level species.

Evaluation of late vegetative and reproductive stage soybeans for resistance to soybean aphid (Hemiptera: Aphididae).

PubMed

Prochaska, T J; Pierson, L M; Baldin, E L L; Hunt, T E; Heng-Moss, T M; Reese, J C

2013-04-01

The soybean aphid, Aphis glycines Matsumura, has become the most significant soybean [Glycine max (L.) Merrill] insect pest in the north central soybean production region of North America. The objectives of this research were to measure selected genotypes for resistance to the soybean aphid in the later vegetative and reproductive stages under field conditions, and confirm the presence of tolerance in KS4202. The results from 2007 to 2011 indicate that KS4202 can support aphid populations with minimal yield loss at levels where significant yield loss would be expected in most other genotypes. The common Nebraska cultivar, 'Asgrow 2703', appears to show signs of tolerance as well. None of the yield parameters were significantly different between the aphid infested and noninfested treatments. Based on our results, genotypes may compensate for aphid feeding in different ways. Asgrow 2703 appears to produce a similar number of seeds as its noninfested counterpart, although the seeds produced are slightly smaller. Field evaluation of tolerance in KS4202 indicated a yield loss of only 13% at 34,585-53,508 cumulative aphid-days, when 24-36% yield loss would have been expected.

National Plant Diagnostic Network, Taxonomic training videos: Aphids under the microscope - Cerataphis brasiliensis

USDA-ARS?s Scientific Manuscript database

Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides provides training to identify the palm aphid, Cerataphis brasiliensis, using a compound microscope and an electronic identification key called “LUCID.” The video demonstrates key morphological structures...

Relationships Between Aphids (Insecta: Homoptera: Aphididae) and Slugs (Gastropoda: Stylommatophora: Agriolimacidae) Pests of Legumes (Fabaceae: Lupinus)

PubMed Central

Kozłowski, Jan; Strażyński, Przemysław; Jaskulska, Monika; Kozłowska, Maria

2016-01-01

Lupin plants are frequently damaged by various herbivorous invertebrates. Significant among these are slugs and aphids, which sometimes attack the same plants. Relationships between aphids, slugs and food plant are very interesting. Grazing by these pests on young plants can lead to significant yield losses. There is evidence that the alkaloids present in some lupin plants may reduce grazing by slugs, aphids and other invertebrates. In laboratory study was analyzed the relationships between aphid Aphis craccivora and slug Deroceras reticulatum pests of legumes Lupinus angustifolius. It was found that the presence of aphids significantly reduced slug grazing on the plants. The lupin cultivars with high alkaloid content were found to be less heavily damaged by D. reticulatum, and the development of A. craccivora was found to be inhibited on such plants. PMID:27324580

Change in Biotypic Diversity of Russian Wheat Aphid (Hemiptera: Aphididae) Populations in the United States.

PubMed

Puterka, G J; Giles, K L; Brown, M J; Nicholson, S J; Hammon, R W; Peairs, F B; Randolph, T L; Michaels, G J; Bynum, E D; Springer, T L; Armstrong, J S; Mornhinweg, D W

2015-04-01

A key component of Russian wheat aphid, Diuraphis noxia (Kurdjumov), management has been through planting resistant wheat cultivars. A new biotype, RWA2, appeared in 2003 which caused widespread damage to wheat cultivars containing the Dn4 gene. Biotypic diversity in Russian wheat aphid populations has not been addressed since 2005 when RWA2 dominated the biotype complex. Our objectives were to determine the biotypic diversity in the Central Great Plains and Colorado Plateau at regional (2010, 2011, 2013) and local (2012) levels and detect the presence of new Russian wheat aphid biotypes. Regional and within-field aphid collections were screened against Russian wheat aphid-resistant wheat genotypes containing genes Dn3, Dn4, Dn6, Dn7, Dn9, CI2401; and resistant barley STARS 9301B. In 2010, all aphid collections from Texas were avirulent to the Dn4 resistance gene in wheat. Regional results revealed Dn4 avirulent RWA6 was widespread (55-84%) in populations infesting wheat in both regions. Biotypes RWA1, 2, and 3/7 were equally represented with percentages<20% each while RWA8 was rarely detected. Combining percentages of RWA1, 6, and 8 across regions to estimate avirulence to Dn4 gene revealed high percentages for both 2011 (64-80%) and 2013 (69-90%). In contrast, the biotype structure at the local level differed where biotype percentages varied up to ≥2-fold between fields. No new biotypes were detected; therefore, Dn7, CI2401, and STARS9301B remained resistant to all known Russian wheat aphid biotypes. This study documents a shift to Dn4 avirulent biotypes and serves as a valuable baseline for biotypic diversity in Russian wheat aphid populations prior to the deployment of new Russian wheat aphid-resistant wheat cultivars. Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.

AtWRKY22 promotes susceptibility to aphids and modulates salicylic acid and jasmonic acid signalling.

PubMed

Kloth, Karen J; Wiegers, Gerrie L; Busscher-Lange, Jacqueline; van Haarst, Jan C; Kruijer, Willem; Bouwmeester, Harro J; Dicke, Marcel; Jongsma, Maarten A

2016-05-01

Aphids induce many transcriptional perturbations in their host plants, but the signalling cascades responsible and the effects on plant resistance are largely unknown. Through a genome-wide association (GWA) mapping study in Arabidopsis thaliana, we identified WRKY22 as a candidate gene associated with feeding behaviour of the green peach aphid, Myzus persicae The transcription factor WRKY22 is known to be involved in pathogen-triggered immunity, and WRKY22 gene expression has been shown to be induced by aphids. Assessment of aphid population development and feeding behaviour on knockout mutants and overexpression lines showed that WRKY22 increases susceptibility to M. persicae via a mesophyll-located mechanism. mRNA sequencing analysis of aphid-infested wrky22 knockout plants revealed the up-regulation of genes involved in salicylic acid (SA) signalling and down-regulation of genes involved in plant growth and cell-wall loosening. In addition, mechanostimulation of knockout plants by clip cages up-regulated jasmonic acid (JA)-responsive genes, resulting in substantial negative JA-SA crosstalk. Based on this and previous studies, WRKY22 is considered to modulate the interplay between the SA and JA pathways in response to a wide range of biotic and abiotic stimuli. Its induction by aphids and its role in suppressing SA and JA signalling make WRKY22 a potential target for aphids to manipulate host plant defences. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Genetic Diversity and Genome Complexity of Sugarcane

USDA-ARS?s Scientific Manuscript database

Sugarcane (Saccharum spp.) as a C4 plant, is one of the most efficient crops in converting solar energy into chemical energy. Sugarcane cultivar improvement programs have not yet systematically utilized the most of the genetic sources of yield potential and resistance to stresses that may exist in t...

Sugarcane boiler ash as an amendment for soilless growing media

USDA-ARS?s Scientific Manuscript database

In 2016, research was conducted to investigate the use of sugarcane bagasse ash (SBA) as an amendment to soilless planting media for the production of vegetable seedlings. Typically, the eleven Louisiana sugarcane mills use a portion of the sugarcane bagasse for fuel, producing over 60,000 tons of S...

Coexistence of three specialist aphids on common milkweed, Asclepias syriaca.

PubMed

Smith, R A; Mooney, K A; Agrawal, A A

2008-08-01

Coexistence of host-specific herbivores on plants is believed to be governed by interspecific interactions, but few empirical studies have systematically unraveled these dynamics. We investigated the role of several factors in promoting coexistence among the aphids Aphis nerii, Aphis asclepiadis, and Myzocallis asclepiadis that all specialize on common milkweed (Asclepias syriaca). Competitive exclusion is thought to occur when interspecific competition is stronger than intraspecific competition. Consequently, we investigated whether predators, mutualists, or resource quality affected the strength of intra- vs. interspecific competition among aphids in factorial manipulations of competition with exposure to predation, ants, and variable plant genotypes in three separate experiments. In the predation x competition experiment, predators reduced aphid per capita growth by 66%, but the strength of intra- and interspecific competition did not depend on predators. In the ants x competition experiment, ants reduced per capita growth of A. nerii and M. asclepiadis (neither of which were mutualists with ants) by approximately one-half. In so doing, ants ameliorated the negative effects of these competitors on ant-tended A. asclepiadis by two-thirds, representing a novel benefit of ant-aphid mutualism. Nevertheless, ants alone did not explain the persistence of competitively inferior A. asclepiadis as, even in the presence of ants, interspecific competition remained stronger than intraspecific competition. In the plant genotype x competition experiment, both A. asclepiadis and M. asclepiadis were competitively inferior to A. nerii, with the strength of interspecific competition exceeding that of intraspecific competition by 83% and 23%, respectively. Yet these effects differed among milkweed genotypes, and there were one or more plant genotypes for each aphid species where coexistence was predicted. A synthesis of our results shows that predators play little or no role in

Newly identified resistance to soybean aphid (Aphis glycines) in soybean plant introduction lines

USDA-ARS?s Scientific Manuscript database

Host-plant resistance is potentially efficacious in managing the soybean aphid (SA, Aphis glycines Matsumura), a major invasive pest in northern soybean-production regions of North America. However, development of aphid-resistant soybean has been complicated by the presence of virulent SA biotypes,...

National Plant Diagnostic Network, Taxonomic training videos: Aphids under the microscope - Myzus persicae

USDA-ARS?s Scientific Manuscript database

Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides provides training to identify the green peach aphid, Myzus persicae, using a compound microscope and an electronic identification key called “LUCID.” The video demonstrates key morphological structures t...

National Plant Diagnostic Network, Taxonomic training videos: Aphids under the microscope - Aphis gossypii

USDA-ARS?s Scientific Manuscript database

Training is a critical part of aphid (Hemiptera: Aphididae) identification. This video provides provides training to identify the cotton aphid, Aphis gossypii, using a compound microscope and an electronic identification key called “LUCID.” The video demonstrates key morphological structures that ca...

The phytopathogen Dickeya dadantii (Erwinia chrysanthemi 3937) is a pathogen of the pea aphid.

PubMed

Grenier, Anne-Marie; Duport, Gabrielle; Pagès, Sylvie; Condemine, Guy; Rahbé, Yvan

2006-03-01

Dickeya dadantii (Erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. The sequencing of its genome identified four genes encoding homologues of the Cyt family of insecticidal toxins from Bacillus thuringiensis, which are not present in the close relative Pectobacterium carotovorum subsp. atrosepticum. The pathogenicity of D. dadantii was tested on the pea aphid Acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, either by septic injury or by oral infection. The lethal inoculum dose was calculated to be as low as 10 ingested bacterial cells. A D. dadantii mutant with the four cytotoxin genes deleted showed a reduced per os virulence for A. pisum, highlighting the potential role of at least one of these genes in pathogenicity. Since only one bacterial pathogen of aphids has been previously described (Erwinia aphidicola), other species from the same bacterial group were tested. The pathogenic trait for aphids was shown to be widespread, albeit variable, within the phytopathogens, with no link to phylogenetic positioning in the Enterobacteriaceae. Previously characterized gut symbionts from thrips (Erwinia/Pantoea group) were also highly pathogenic to the aphid, whereas the potent entomopathogen Photorhabdus luminescens was not. D. dadantii is not a generalist insect pathogen, since it has low pathogenicity for three other insect species (Drosophila melanogaster, Sitophilus oryzae, and Spodoptera littoralis). D. dadantii was one of the most virulent aphid pathogens in our screening, and it was active on most aphid instars, except for the first one, probably due to anatomical filtering. The observed difference in virulence toward apterous and winged aphids may have an ecological impact, and this deserves specific attention in future research.

Response of Russian wheat aphid resistance in wheat and barley to four Diuraphis (Hemiptera: Aphididae) species.

PubMed

Puterka, Gary J; Scott, J Nicholson; Brown, Michael J; Hammon, R W

2013-04-01

Three Diuraphis species, Diuraphis frequens (Walker), Diuraphis mexicana (McVicar Baker), and Diuraphis tritici (Gillette), were known to exist in the United States before the 1986 appearance of the Russian wheat aphid, Diuraphis noxia Kurdjumov. The Russian wheat aphid soon became a significant pest of wheat although other endemic Diuraphis species were known to infest wheat. Wheat and barley entries resistant and susceptible to Russian wheat aphid biotype 2 were evaluated against all four Diuraphis species to determine their host interrelationships. Leaf chlorosis, leaf roll, leaf number, plant height, and infestation levels were assessed 21 d after the plants were infested by aphids in a no-choice caged environment. D. mexicana was unable to survive on wheat by 21 d after infestation and effects on the plant damage variables were negligible. D. frequens survived at low levels on resistant and susceptible plant entries and had a low impact on plant damage and growth. Russian wheat aphid biotype 2 and D. tritici were damaged most wheat and barley lines except the Russian wheat aphid biotype 2-resistant wheat lines containing genes from Dn7, STARS 2414-11, and CI2401; and resistant barley containing genes from STARS 9577B and 9301B. Russian wheat aphid biotype 2 and D. tritici reduced the growth of resistant plants by 25-50% and susceptible entries by 65-75%. Reductions at this level are typical under no-choice studies but resistant cultivars do not have these reductions under field conditions. The Russian wheat aphid biotype 2 resistant wheat lines would be effective in managing both wheat pest species.

Aphid vector population density determines the emergence of necrogenic satellite RNAs in populations of cucumber mosaic virus.

PubMed

Betancourt, Mónica; Fraile, Aurora; Milgroom, Michael G; García-Arenal, Fernando

2016-06-01

The satellite RNAs of cucumber mosaic virus (CMV) that induce systemic necrosis in tomato plants (N-satRNA) multiply to high levels in the infected host while severely depressing CMV accumulation and, hence, its aphid transmission efficiency. As N-satRNAs are transmitted into CMV particles, the conditions for N-satRNA emergence are not obvious. Model analyses with realistic parameter values have predicted that N-satRNAs would invade CMV populations only when transmission rates are high. Here, we tested this hypothesis experimentally by passaging CMV or CMV+N-satRNAs at low or high aphid densities (2 or 8 aphids/plant). As predicted, high aphid densities were required for N-satRNA emergence. The results showed that at low aphid densities, random effects due to population bottlenecks during transmission dominate the epidemiological dynamics of CMV/CMV+N-satRNA. The results suggest that maintaining aphid populations at low density will prevent the emergence of highly virulent CMV+N-satRNA isolates.

Vegetable seedling production with sugarcane bagasse ash

USDA-ARS?s Scientific Manuscript database

The eleven sugarcane mills in Louisiana processed 380,000 ac and 12.8 million tons of harvested sugarcane in 2014, producing 1.5 million tons of raw sugar (brown sugar), and an estimated 3 million tons of the fibrous plant residue called bagasse. Bagasse is the fibrous material remaining after remov...

Spatial Distribution and Sampling Plans With Fixed Level of Precision for Citrus Aphids (Hom., Aphididae) on Two Orange Species.

PubMed

Kafeshani, Farzaneh Alizadeh; Rajabpour, Ali; Aghajanzadeh, Sirous; Gholamian, Esmaeil; Farkhari, Mohammad

2018-04-02

Aphis spiraecola Patch, Aphis gossypii Glover, and Toxoptera aurantii Boyer de Fonscolombe are three important aphid pests of citrus orchards. In this study, spatial distributions of the aphids on two orange species, Satsuma mandarin and Thomson navel, were evaluated using Taylor's power law and Iwao's patchiness. In addition, a fixed-precision sequential sampling plant was developed for each species on the host plant by Green's model at precision levels of 0.25 and 0.1. The results revealed that spatial distribution parameters and therefore the sampling plan were significantly different according to aphid and host plant species. Taylor's power law provides a better fit for the data than Iwao's patchiness regression. Except T. aurantii on Thomson navel orange, spatial distribution patterns of the aphids were aggregative on both citrus. T. aurantii had regular dispersion pattern on Thomson navel orange. Optimum sample size of the aphids varied from 30-2061 and 1-1622 shoots on Satsuma mandarin and Thomson navel orange based on aphid species and desired precision level. Calculated stop lines of the aphid species on Satsuma mandarin and Thomson navel orange ranged from 0.48 to 19 and 0.19 to 80.4 aphids per 24 shoots according to aphid species and desired precision level. The performance of the sampling plan was validated by resampling analysis using resampling for validation of sampling plans (RVSP) software. This sampling program is useful for IPM program of the aphids in citrus orchards.

Proteomic Profiling of Cereal Aphid Saliva Reveals Both Ubiquitous and Adaptive Secreted Proteins

PubMed Central

Wilkinson, Tom L.

2013-01-01

The secreted salivary proteins from two cereal aphid species, Sitobion avenae and Metopolophium dirhodum, were collected from artificial diets and analysed by tandem mass spectrometry. Protein identification was performed by searching MS data against the official protein set from the current pea aphid (Acyrthosiphon pisum) genome assembly and revealed 12 and 7 proteins in the saliva of S. avenae and M. dirhodum, respectively. When combined with a comparable dataset from A. pisum, only three individual proteins were common to all the aphid species; two paralogues of the GMC oxidoreductase family (glucose dehydrogenase; GLD) and ACYPI009881, an aphid specific protein previously identified as a putative component of the salivary sheath. Antibodies were designed from translated protein sequences obtained from partial cDNA sequences for ACYPI009881 and both saliva associated GLDs. The antibodies detected all parent proteins in secreted saliva from the three aphid species, but could only detect ACYPI009881, and not saliva associated GLDs, in protein extractions from the salivary glands. This result was confirmed by immunohistochemistry using whole and sectioned salivary glands, and in addition, localised ACYPI009881 to specific cell types within the principal salivary gland. The implications of these findings for the origin of salivary components and the putative role of the proteins identified are discussed in the context of our limited understanding of the functional relationship between aphid saliva and the plants they feed on. The mass spectrometry data have been deposited to the ProteomeXchange and can be accessed under the identifier PXD000113. PMID:23460852

Proteomic profiling of cereal aphid saliva reveals both ubiquitous and adaptive secreted proteins.

PubMed

Rao, Sohail A K; Carolan, James C; Wilkinson, Tom L

2013-01-01

The secreted salivary proteins from two cereal aphid species, Sitobion avenae and Metopolophium dirhodum, were collected from artificial diets and analysed by tandem mass spectrometry. Protein identification was performed by searching MS data against the official protein set from the current pea aphid (Acyrthosiphon pisum) genome assembly and revealed 12 and 7 proteins in the saliva of S. avenae and M. dirhodum, respectively. When combined with a comparable dataset from A. pisum, only three individual proteins were common to all the aphid species; two paralogues of the GMC oxidoreductase family (glucose dehydrogenase; GLD) and ACYPI009881, an aphid specific protein previously identified as a putative component of the salivary sheath. Antibodies were designed from translated protein sequences obtained from partial cDNA sequences for ACYPI009881 and both saliva associated GLDs. The antibodies detected all parent proteins in secreted saliva from the three aphid species, but could only detect ACYPI009881, and not saliva associated GLDs, in protein extractions from the salivary glands. This result was confirmed by immunohistochemistry using whole and sectioned salivary glands, and in addition, localised ACYPI009881 to specific cell types within the principal salivary gland. The implications of these findings for the origin of salivary components and the putative role of the proteins identified are discussed in the context of our limited understanding of the functional relationship between aphid saliva and the plants they feed on. The mass spectrometry data have been deposited to the ProteomeXchange and can be accessed under the identifier PXD000113.

Integrated management of bermudagrass (Cynodon dactylon) in sugarcane

USDA-ARS?s Scientific Manuscript database

Bermudagrass is a difficult perennial weed to manage in Louisiana sugarcane. Research was conducted to compare interrow tillage practice, postharvest residue management, and herbicide placement on bermudagrass proliferation and sugarcane yield. Tillage frequencies included conventional (four tillage...

Utilization of ladybird beetles to curb aphids in strawberry high tunnels: preliminary results

USDA-ARS?s Scientific Manuscript database

Native and exotic aphid species continue to pose a threat to the successful cultivation of small fruits in greenhouses, glasshouses, and high tunnels throughout the World. There is considerable interest in using biological controls (predators and parasitoids) to manage aphids in lieu of synthetic in...

Water sustainability assessment in Brazilian sugarcane expansion area

NASA Astrophysics Data System (ADS)

Scarpare, F. V.; Ruiz-Correa, S. T.; Hernandes, T. A.; Scanlon, B. R.; Picoli, M. C. A.; Bonomi, A.

2016-12-01

Due to the increasing demand for ethanol, sugarcane is expanding into Cerrado (Savannahs), where edaphoclimatic characteristics differ significantly from traditional areas in South-eastern Brazil. It is expected that the sugarcane will be irrigated in those areas to increase yields and ensure stable production. The main objective is to assess the sugarcane land occupation and its dynamics relating its occurrence with the potential and actual yields, the irrigation needs, the production costs, and the water footprint in Paranaíba watershed (222,593 km2 drainage area). The Agroecological Zone Model - FAO was used in order to provide essential data for yield and water requirement assessment. For sugarcane stalk yield estimation, several improvements have been made allowing this tool to assess different irrigation scenarios. In this study, full irrigation which aims to replace 100% of the water deficit until senescence period was considered. The sugarcane occupation and expansion was assessed through EVI approach from 2009/2010 to 2012/2013 crop seasons. It was possible to identify that most part of sugarcane occupation is concentrated in the central area, which presents less potential for yield gain through irrigation and significant water availability issues. With regard to the expansion, an increase of 54% of cane occupation (from 616,899 to 946,589 ha) was detected during the assessed period showing that the main dynamic occurred in central part towards west side and at less extent, to southeaster side. The irrigation management were responsible for increase, on average, 108% of yields while decreasing 42% of water footprints. Simulated yields combine with CanaSoft model estimated a 30% decline in production cost. Although several aspects such as land price and infrastructure must to be considered, in conclusion, the expansion dynamic agrees to the areas with greater yield gain potential through irrigation, lower sugarcane production costs and water footprint

SIEVE ELEMENT-LINING CHAPERONE1 Restricts Aphid Feeding on Arabidopsis during Heat Stress.

PubMed

Kloth, Karen J; Busscher-Lange, Jacqueline; Wiegers, Gerrie L; Kruijer, Willem; Buijs, Gonda; Meyer, Rhonda C; Albrectsen, Benedicte R; Bouwmeester, Harro J; Dicke, Marcel; Jongsma, Maarten A

2017-10-01

The role of phloem proteins in plant resistance to aphids is still largely elusive. By genome-wide association mapping of aphid behavior on 350 natural Arabidopsis thaliana accessions, we identified the small heat shock-like SIEVE ELEMENT-LINING CHAPERONE1 ( SLI1 ). Detailed behavioral studies on near-isogenic and knockout lines showed that SLI1 impairs phloem feeding. Depending on the haplotype, aphids displayed a different duration of salivation in the phloem. On sli1 mutants, aphids prolonged their feeding sessions and ingested phloem at a higher rate than on wild-type plants. The largest phenotypic effects were observed at 26°C, when SLI1 expression is upregulated. At this moderately high temperature, sli1 mutants suffered from retarded elongation of the inflorescence and impaired silique development. Fluorescent reporter fusions showed that SLI1 is confined to the margins of sieve elements where it lines the parietal layer and colocalizes in spherical bodies around mitochondria. This localization pattern is reminiscent of the clamp-like structures observed in previous ultrastructural studies of the phloem and shows that the parietal phloem layer plays an important role in plant resistance to aphids and heat stress. © 2017 American Society of Plant Biologists. All rights reserved.

Presence of the Aphid, Chaetosiphon fragaefolii, on Strawberry in Argentina

PubMed Central

Cédola, Claudia; Grecob, Nancy

2010-01-01

Seasonal abundance of the strawberry aphid complex under different agronomic practices in the outskirts of La Plata, Argentina was studied on strawberry, Fragaria x ananassa Duchesne (Rosales: Rosaceae). Aphid densities were low in strawberry fields in which insecticides and fungicides were used. In addition to Aphis gossypii, Aphis fabae, Mysus persicae and Macrosiphum euphorbiae, the aphid, Chaetosiphon fragaefolii (Cockerell) (Homoptera: Aphididae), was recorded for the first time in this horticultural area. Life history and some demographic parameters were calculated for C. fragaefolii. The mean duration of nymphal stages was 10.44 days, the oviposition period was 11.8 days, and the mean number of nymph/female/day was 2.4 ± 0.3. Demographic parameters analyzed included the net reproductive rate Ro = 14.55 ± 0.096 nymph/female, generation time T=16.91 ± 0.035 days, and the intrinsic rate of increase rm = 0.158 ± (0.004). No parasites were found associated with C. fragaefolli. The pathogenic fungus, Entomophthora planchoniana Cornu (Zygomycetes: Entomophthorales) was the main mortality factor. Although aphids are not the main pests in strawberry fields, C. fragaefolii can be a serious problem because it can transmit several virus diseases of strawberry. Greater knowledge of life history traits and mortality factors of this species is needed in order to design appropriate control strategies. PMID:20569141

Presence of the aphid, Chaetosiphon fragaefolii, on strawberry in Argentina.

PubMed

Cédola, Claudia; Grecob, Nancy

2010-01-01

Seasonal abundance of the strawberry aphid complex under different agronomic practices in the outskirts of La Plata, Argentina was studied on strawberry, Fragaria x ananassa Duchesne (Rosales: Rosaceae). Aphid densities were low in strawberry fields in which insecticides and fungicides were used. In addition to Aphis gossypii, Aphis fabae, Mysus persicae and Macrosiphum euphorbiae, the aphid, Chaetosiphon fragaefolii (Cockerell) (Homoptera: Aphididae), was recorded for the first time in this horticultural area. Life history and some demographic parameters were calculated for C. fragaefolii. The mean duration of nymphal stages was 10.44 days, the oviposition period was 11.8 days, and the mean number of nymph/female/day was 2.4 +/- 0.3. Demographic parameters analyzed included the net reproductive rate R(o) = 14.55 +/- 0.096 nymph/female, generation time T=16.91 +/- 0.035 days, and the intrinsic rate of increase r(m) = 0.158 +/- (0.004). No parasites were found associated with C. fragaefolli. The pathogenic fungus, Entomophthora planchoniana Cornu (Zygomycetes: Entomophthorales) was the main mortality factor. Although aphids are not the main pests in strawberry fields, C. fragaefolii can be a serious problem because it can transmit several virus diseases of strawberry. Greater knowledge of life history traits and mortality factors of this species is needed in order to design appropriate control strategies.

Physiological and transcriptional analyses of developmental stages along sugarcane leaf.

PubMed

Mattiello, Lucia; Riaño-Pachón, Diego Mauricio; Martins, Marina Camara Mattos; da Cruz, Larissa Prado; Bassi, Denis; Marchiori, Paulo Eduardo Ribeiro; Ribeiro, Rafael Vasconcelos; Labate, Mônica T Veneziano; Labate, Carlos Alberto; Menossi, Marcelo

2015-12-29

Sugarcane is one of the major crops worldwide. It is cultivated in over 100 countries on 22 million ha. The complex genetic architecture and the lack of a complete genomic sequence in sugarcane hamper the adoption of molecular approaches to study its physiology and to develop new varieties. Investments on the development of new sugarcane varieties have been made to maximize sucrose yield, a trait dependent on photosynthetic capacity. However, detailed studies on sugarcane leaves are scarce. In this work, we report the first molecular and physiological characterization of events taking place along a leaf developmental gradient in sugarcane. Photosynthetic response to CO2 indicated divergence in photosynthetic capacity based on PEPcase activity, corroborated by activity quantification (both in vivo and in vitro) and distinct levels of carbon discrimination on different segments along leaf length. Additionally, leaf segments had contrasting amount of chlorophyll, nitrogen and sugars. RNA-Seq data indicated a plethora of biochemical pathways differentially expressed along the leaf. Some transcription factors families were enriched on each segment and their putative functions corroborate with the distinct developmental stages. Several genes with higher expression in the middle segment, the one with the highest photosynthetic rates, were identified and their role in sugarcane productivity is discussed. Interestingly, sugarcane leaf segments had a different transcriptional behavior compared to previously published data from maize. This is the first report of leaf developmental analysis in sugarcane. Our data on sugarcane is another source of information for further studies aiming to understand and/or improve C4 photosynthesis. The segments used in this work were distinct in their physiological status allowing deeper molecular analysis. Although limited in some aspects, the comparison to maize indicates that all data acquired on one C4 species cannot always be easily

Cross-resistance between the Mexican Rice Borer and the Sugarcane Borer (Lepidoptera: Crambidae): A Case Study Using Sugarcane Breeding Populations

USDA-ARS?s Scientific Manuscript database

The sugarcane borer (SCB) (Diatraea saccharalis) and Mexican rice borer (MRB) (Eoreuma loftini) are two economically important pests of sugarcane in the USA. Because of similarities in larval feeding behavior, selecting for resistance to one species could provide resistance to the other, a phenomeno...

Life history and morphological plasticity of three biotypes of soybean aphid (Aphis glycines)

USDA-ARS?s Scientific Manuscript database

The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is a pest of soybean, Glycine max (L.) Merr. (Fabaceae), from eastern Asia that was first reported in North America in 2000. The influence of temperature on plasticity of life history and morphological traits of the soybean aphid ha...

Impact of biotechnology on sugarcane agriculture and industry

USDA-ARS?s Scientific Manuscript database

There are nine key issues that can influence the productivity and sustainability of the sugarcane industry. These include land, soil fertility, water, variety, planting density, crop protection, cultural practices, harvesting and processing, and information technology. To all sugarcane farmers, it r...

Ants farm subterranean aphids mostly in single clone groups - an example of prudent husbandry for carbohydrates and proteins?

PubMed Central

2012-01-01

Background Mutualistic interactions are wide-spread but the mechanisms underlying their evolutionary stability and ecological dynamics remain poorly understood. Cultivation mutualisms in which hosts consume symbionts occur in phylogenetically diverse groups, but often have symbiont monocultures for each host. This is consistent with the prediction that symbionts should avoid coexistence with other strains so that host services continue to benefit relatives, but it is less clear whether hosts should always favor monocultures and what mechanisms they might have to manipulate symbiont diversity. Few mutualisms have been studied in sufficient genetic detail to address these issues, so we decided to characterize symbiont diversity in the complex mutualism between multiple root aphid species and Lasius flavus ants. After showing elsewhere that three of these aphid species have low dispersal and mostly if not exclusively asexual reproduction, we here investigate aphid diversity within and between ant nest mounds. Results The three focal species (Geoica utricularia, Forda marginata and Tetraneura ulmi) had considerable clonal diversity at the population level. Yet more than half of the ant mounds contained just a single aphid species, a significantly higher percentage than expected from a random distribution. Over 60% of these single-species mounds had a single aphid clone, and clones tended to persist across subsequent years. Whenever multiple species/clones co-occurred in the same mound, they were spatially separated with more than 95% of the aphid chambers containing individuals of a single clone. Conclusions L. flavus “husbandry” is characterized by low aphid “livestock” diversity per colony, especially at the nest-chamber level, but it lacks the exclusive monocultures known from other cultivation mutualisms. The ants appear to eat most of the early instar aphids, so that adult aphids are unlikely to face limited phloem resources and scramble competition with

Characterization of eight Russian wheat aphid (Hemiptera: Aphididae) biotypes using two-category resistant-susceptible plant responses.

PubMed

Puterka, G J; Nicholson, S J; Brown, M J; Cooper, W R; Peairs, F B; Randolph, T L

2014-06-01

Eight biotypes of the Russian wheat aphid, Diuraphis noxia (Kurdjumov), have been discovered in the United States since 2003. Biotypes are identified by the distinct feeding damage responses they produce on wheat carrying different Russian wheat aphid resistance genes, namely, from Dn1 to Dn9. Each Russian wheat aphid biotype has been named using plant damage criteria and virulence categories that have varied between studies. The study was initiated to compare the plant damage caused by all the eight known Russian wheat aphid biotypes, and analyze the results to determine how Russian wheat aphid virulence should be classified. Each Russian wheat aphid biotype was evaluated on 16 resistant or susceptible cereal genotypes. Plant damage criteria included leaf roll, leaf chlorosis, and plant height. The distribution of chlorosis ratings followed a bimodal pattern indicating two categories of plant responses, resistant or susceptible. Correlations were significant between chlorosis ratings and leaf roll (r(2) = 0.72) and between chlorosis ratings and plant height (r(2) = 0.48). The response of 16 cereal genotypes to feeding by eight Russian wheat aphid biotypes found RWA1, RWA2, RWA6, and RWA8 to differ in virulence, while Russian wheat aphid biotypes RWA3, RWA4, RWA5, and RWA7 produced similar virulence profiles. These biotypes have accordingly been consolidated to what is hereafter referred to as RWA3/7. Our results indicated that the five main biotypes RWA1, RWA2, RWA3/7, RWA6, and RWA8 can be identified using only four wheat genotypes containing Dn3, Dn4, Dn6, and Dn9.

Chemical characteristics of normal, woolly apple aphid-damaged, and mechanically damaged twigs of six apple cultivars, measured in autumn wood.

PubMed

Zhou, Hong-Xu; Wang, Xi-Cun; Yu, Yi; Tan, Xiu-Mei; Cheng, Zai-Quan; Zhang, An-Sheng; Men, Xing-Yuan; Li-Li, Li

2013-04-01

Chemical characteristics of normal, woolly apple aphid-damaged, and mechanically damaged twigs of six apple cultivars: Red Fuji, Golden Delicious, Qinguan, Zhaojin 108, Starkrimson, and Red General, were examined in autumn wood to provide abetter understanding of factors related to cultivar resistance to the woolly apple aphid, Eriosoma lanigerum (Hausmann). Chemical measures examined included soluble sugars, soluble proteins and amino acids, total phenolics, and polyphenol oxidase (that enhances the resistance of plants to insects) and superoxide dismutase, peroxidase, and catalase (that degrade waste products in plants). Soluble sugar, protein, and amino acid contents in normal (undamaged) twigs of Red Fuji, aphid-susceptible cultivar, were higher than in mechanically damaged and aphid-damaged twigs. Total phenolic compounds, an important group of defensive compounds against aphids, increased by 30.5 and 6.0% in mechanically damaged twigs of Qinguan and Zhaojin 108, respectively, and decreased by 21.7 and 16.1% in aphid-damaged twigs of Red Fuji and Red General, respectively. Compared with normal twigs, in aphid-damaged twigs, superoxide dismutase, peroxidase, and polyphenol activity all decreased in Red Fuji. The resistance of some apple cultivars to woolly apple aphid during the growth of autumn shoots was related to several of the physiological indices we monitored. The thin epidermis of callus tissue over healed wounds showed increased susceptibility to the attack by woolly apple aphid. Apple cultivar Qinguan with the highest level of resistance to woolly apple aphid in autumn had increased in amino acid, total phenolic compound levels, and enzyme activity after aphid feeding.

Maintaining genetic diversity and population panmixia through dispersal and not gene flow in a Holocyclic heteroecious aphid species

USDA-ARS?s Scientific Manuscript database

Heteroecious holocyclic aphids alternate between sexual and asexual reproduction on primary and secondary hosts, respectively. Most of these aphids are generalists, but the aphid specialist Aphis glycines survives only on the primary host buckthorn (Rhamnus spp.) and the secondary host soybean (Gly...

Protein digestion in cereal aphids (Sitobion avenae) as a target for plant defence by endogenous proteinase inhibitors.

PubMed

Pyati, Prashant; Bandani, Ali R; Fitches, Elaine; Gatehouse, John A

2011-07-01

Gut extracts from cereal aphids (Sitobion avenae) showed significant levels of proteolytic activity, which was inhibited by reagents specific for cysteine proteases and chymotrypsin-like proteases. Gut tissue contained cDNAs encoding cathepsin B-like cysteine proteinases, similar to those identified in the closely related pea aphid (Acyrthosiphon pisum). Analysis of honeydew (liquid excreta) from cereal aphids fed on diet containing ovalbumin showed that digestion of ingested proteins occurred in vivo. Protein could partially substitute for free amino acids in diet, although it could not support complete development. Recombinant wheat proteinase inhibitors (PIs) fed in diet were antimetabolic to cereal aphids, even when normal levels of free amino acids were present. PIs inhibited proteolysis by aphid gut extracts in vitro, and digestion of protein fed to aphids in vivo. Wheat subtilisin/chymotrypsin inhibitor, which was found to inhibit serine and cysteine proteinases, was more effective in both inhibitory and antimetabolic activity than wheat cystatin, which inhibited cysteine proteases only. Digestion of ingested protein is unlikely to contribute significantly to nutritional requirements when aphids are feeding on phloem, and the antimetabolic activity of dietary proteinase inhibitors is suggested to result from effects on proteinases involved in degradation of endogenous proteins. Copyright © 2011 Elsevier Ltd. All rights reserved.

Relationships Between Aphids (Insecta: Homoptera: Aphididae) and Slugs (Gastropoda: Stylommatophora: Agriolimacidae) Pests of Legumes (Fabaceae: Lupinus).

PubMed

Kozłowski, Jan; Strażyński, Przemysław; Jaskulska, Monika; Kozłowska, Maria

2016-01-01

Lupin plants are frequently damaged by various herbivorous invertebrates. Significant among these are slugs and aphids, which sometimes attack the same plants. Relationships between aphids, slugs and food plant are very interesting. Grazing by these pests on young plants can lead to significant yield losses. There is evidence that the alkaloids present in some lupin plants may reduce grazing by slugs, aphids and other invertebrates. In laboratory study was analyzed the relationships between aphid Aphis craccivora and slug Deroceras reticulatum pests of legumes Lupinus angustifolius. It was found that the presence of aphids significantly reduced slug grazing on the plants. The lupin cultivars with high alkaloid content were found to be less heavily damaged by D. reticulatum, and the development of A. craccivora was found to be inhibited on such plants. © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

Sugarcane Water Stress Tolerance Mechanisms and Its Implications on Developing Biotechnology Solutions

PubMed Central

Ferreira, Thais H. S.; Tsunada, Max S.; Bassi, Denis; Araújo, Pedro; Mattiello, Lucia; Guidelli, Giovanna V.; Righetto, Germanna L.; Gonçalves, Vanessa R.; Lakshmanan, Prakash; Menossi, Marcelo

2017-01-01

Sugarcane is a unique crop with the ability to accumulate high levels of sugar and is a commercially viable source of biomass for bioelectricity and second-generation bioethanol. Water deficit is the single largest abiotic stress affecting sugarcane productivity and the development of water use efficient and drought tolerant cultivars is an imperative for all major sugarcane producing countries. This review summarizes the physiological and molecular studies on water deficit stress in sugarcane, with the aim to help formulate more effective research strategies for advancing our knowledge on genes and mechanisms underpinning plant response to water stress. We also overview transgenic studies in sugarcane, with an emphasis on the potential strategies to develop superior sugarcane varieties that improve crop productivity in drought-prone environments. PMID:28690620

Potential for Genetic Improvement of Sugarcane as a Source of Biomass for Biofuels

PubMed Central

Hoang, Nam V.; Furtado, Agnelo; Botha, Frederik C.; Simmons, Blake A.; Henry, Robert J.

2015-01-01

Sugarcane (Saccharum spp. hybrids) has great potential as a major feedstock for biofuel production worldwide. It is considered among the best options for producing biofuels today due to an exceptional biomass production capacity, high carbohydrate (sugar + fiber) content, and a favorable energy input/output ratio. To maximize the conversion of sugarcane biomass into biofuels, it is imperative to generate improved sugarcane varieties with better biomass degradability. However, unlike many diploid plants, where genetic tools are well developed, biotechnological improvement is hindered in sugarcane by our current limited understanding of the large and complex genome. Therefore, understanding the genetics of the key biofuel traits in sugarcane and optimization of sugarcane biomass composition will advance efficient conversion of sugarcane biomass into fermentable sugars for biofuel production. The large existing phenotypic variation in Saccharum germplasm and the availability of the current genomics technologies will allow biofuel traits to be characterized, the genetic basis of critical differences in biomass composition to be determined, and targets for improvement of sugarcane for biofuels to be established. Emerging options for genetic improvement of sugarcane for the use as a bioenergy crop are reviewed. This will better define the targets for potential genetic manipulation of sugarcane biomass composition for biofuels. PMID:26636072

Nitrate Paradigm Does Not Hold Up for Sugarcane

PubMed Central

Robinson, Nicole; Brackin, Richard; Vinall, Kerry; Soper, Fiona; Holst, Jirko; Gamage, Harshi; Paungfoo-Lonhienne, Chanyarat; Rennenberg, Heinz; Lakshmanan, Prakash; Schmidt, Susanne

2011-01-01

Modern agriculture is based on the notion that nitrate is the main source of nitrogen (N) for crops, but nitrate is also the most mobile form of N and easily lost from soil. Efficient acquisition of nitrate by crops is therefore a prerequisite for avoiding off-site N pollution. Sugarcane is considered the most suitable tropical crop for biofuel production, but surprisingly high N fertilizer applications in main producer countries raise doubt about the sustainability of production and are at odds with a carbon-based crop. Examining reasons for the inefficient use of N fertilizer, we hypothesized that sugarcane resembles other giant tropical grasses which inhibit the production of nitrate in soil and differ from related grain crops with a confirmed ability to use nitrate. The results of our study support the hypothesis that N-replete sugarcane and ancestral species in the Andropogoneae supertribe strongly prefer ammonium over nitrate. Sugarcane differs from grain crops, sorghum and maize, which acquired both N sources equally well, while giant grass, Erianthus, displayed an intermediate ability to use nitrate. We conclude that discrimination against nitrate and a low capacity to store nitrate in shoots prevents commercial sugarcane varieties from taking advantage of the high nitrate concentrations in fertilized soils in the first three months of the growing season, leaving nitrate vulnerable to loss. Our study addresses a major caveat of sugarcane production and affords a strong basis for improvement through breeding cultivars with enhanced capacity to use nitrate as well as through agronomic measures that reduce nitrification in soil. PMID:21552564

Simulated hydroclimatic impacts of projected Brazilian sugarcane expansion

NASA Astrophysics Data System (ADS)

Georgescu, M.; Lobell, D. B.; Field, C. B.; Mahalov, A.

2013-03-01

Sugarcane area is currently expanding in Brazil, largely in response to domestic and international demand for sugar-based ethanol. To investigate the potential hydroclimatic impacts of future expansion, a regional climate model is used to simulate 5 years of a scenario in which cerrado and cropland areas (~1.1E6 km2) within south-central Brazil are converted to sugarcane. Results indicate a cooling of up to ~1.0°C during the peak of the growing season, mainly as a result of increased albedo of sugarcane relative to the previous landscape. After harvest, warming of similar magnitude occurs from a significant decline in evapotranspiration and a repartitioning toward greater sensible heating. Overall, annual temperature changes from large-scale conversion are expected to be small because of offsetting reductions in net radiation absorption and evapotranspiration. The decline in net water flux from land to the atmosphere implies a reduction in regional precipitation, which is consistent with progressively decreasing simulated average rainfall for the study period, upon conversion to sugarcane. However, rainfall changes were not robust across three ensemble members. The results suggest that sugarcane expansion will not drastically alter the regional energy or water balance, but could result in important local and seasonal effects.

Sugarcane White Leaf Disease Incidences and Population Dynamic of Leafhopper Insect Vectors in Sugarcane Plantations in Northeast Thailand.

PubMed

Rattanabunta, Chiranan; Hanboonsong, Yupa

2015-04-01

The work consisted of two experiments, i.e. Experiment 1 was conducted under controlled environments where sugarcane plants were used as hosts. This investigation aimed to monitor the occurrence of the Sugarcane White Leaf disease and the abundance of Leafhopper insect vectors and also the work aimed to provide useful information in understanding some aspects on epidemiology of the Sugarcane White Leaf disease. A Completely Randomized Design with three replications was used to justify growth and development of Leafhopper insects as affected by different temperatures: 20 (T1), 25 (T2), 30 (T3) and 35 degrees C (T4). Experiment 2 was carried out to determine the numbers of Leafhopper insects with the use of light traps in the sugarcane Field 1 (ratoon plants), Field 2 (newly planted), Field 3 (newly planted) and Field 4 (ratoon plants). The results of Experiment 1 showed that growth and development of Leafhopper insects were highly affected by temperatures i.e. the higher the environmental temperature the faster the growth and development of the insects to reach its full adulthood. At 20 degrees C, Leafhopper insects took 12 days to lay eggs whereas at 25 degrees C the insects took only 6 days. Male reached its adulthood approximately 9 days earlier than female when cultured at 25 degrees C and became approximately one week at 30 degrees C or higher. The results of Experiment 2 showed that the majority of Leafhopper insects were found within the months of June and July for both newly planted and ratoon crops. A small amount was found in May and August with an exceptional case of Field 4 where the highest number of Leafhopper insects was found in April followed by June and July. For Sugarcane White Leaf disease, the disease was found in all months of the year except February for Fields 2 and 3. Newly planted sugarcane plants attained much smaller percentages of disease than those of the ratoon plants.

Comparative transcriptome analysis of Gossypium hirsutum L. in response to sap sucking insects: aphid and whitefly

PubMed Central

2013-01-01

Background Cotton (Gossypium hirsutum L.) is a major fiber crop that is grown worldwide; it faces extensive damage from sap-sucking insects, including aphids and whiteflies. Genome-wide transcriptome analysis was performed to understand the molecular details of interaction between Gossypium hirsutum L. and sap-sucking pests, namely Aphis gossypii (Aphid) and Bemisia tabacci (Whiteflies). Roche’s GS-Titanium was used to sequence transcriptomes of cotton infested with aphids and whiteflies for 2 h and 24 h. Results A total of 100935 contigs were produced with an average length of 529 bp after an assembly in all five selected conditions. The Blastn of the non-redundant (nr) cotton EST database resulted in the identification of 580 novel contigs in the cotton plant. It should be noted that in spite of minimal physical damage caused by the sap-sucking insects, they can change the gene expression of plants in 2 h of infestation; further change in gene expression due to whiteflies is quicker than due to aphids. The impact of the whitefly 24 h after infestation was more or less similar to that of the aphid 2 h after infestation. Aphids and whiteflies affect many genes that are regulated by various phytohormones and in response to microbial infection, indicating the involvement of complex crosstalk between these pathways. The KOBAS analysis of differentially regulated transcripts in response to aphids and whiteflies indicated that both the insects induce the metabolism of amino acids biosynthesis specially in case of whiteflies infestation at later phase. Further we also observed that expression of transcript related to photosynthesis specially carbon fixation were significantly influenced by infestation of Aphids and Whiteflies. Conclusions A comparison of different transcriptomes leads to the identification of differentially and temporally regulated transcripts in response to infestation by aphids and whiteflies. Most of these differentially expressed contigs were

Shifting from clonal to sexual reproduction in aphids: physiological and developmental aspects.

PubMed

Le Trionnaire, Gaël; Hardie, Jim; Jaubert-Possamai, Stéphanie; Simon, Jean-Christophe; Tagu, Denis

2008-08-01

Developmental biology is one of the fastest growing and fascinating research fields in life sciences. Among the wide range of embryonic development, a fundamental difference exists between organisms with sexual or asexual development. Aphids are unusual organisms which display alternative pathways of sexual and asexual development, the orientation of the pathway being determined by environmental conditions. These insects offer an adapted system in which to study developmental plasticity, because a side-by-side comparison of sexual and asexual development can be made in individuals with the same genotype. In this review, we describe the developmental mechanisms that have evolved in aphids for alternative sexual and asexual reproduction. In particular, we discuss how environmental cues orientate the reproductive mode of aphids from signal perception to endocrine regulation, and propose a comparative analysis of sexual and asexual gametogenesis and embryogenesis, which has been possible due to the development of molecular methods. As a result of the recent development of genomic resources in aphids, we expect these species will permit major advances in the study of the genomic basis underlying the choice of developmental fate and multiple reproduction strategies.

Bacterial symbionts, Buchnera, and starvation on wing dimorphism in English grain aphid, Sitobion avenae (F.) (Homoptera: Aphididae)

PubMed Central

Zhang, Fangmei; Li, Xiangrui; Zhang, Yunhui; Coates, Brad; Zhou, Xuguo “Joe”; Cheng, Dengfa

2015-01-01

Wing dimorphism in aphids can be affected by multiple cues, including both biotic (nutrition, crowding, interspecific interactions, the presence of natural enemies, maternal and transgenerational effects, and alarm pheromone) and abiotic factors (temperature, humidity, and photoperiod). The majority of the phloem-feeding aphids carry Buchnera, an obligate symbiotic proteobacteria. Buchnera has a highly reduced genome size, but encode key enzymes in the tryptophan biosynthetic pathway and is crucial for nutritional balance, development and reproduction in aphids. In this study, we investigated the impact of two nutritional-based biotic factors, symbionts and starvation, on the wing dimorphism in the English grain aphid, Sitobion avenae, a devastating insect pest of cereal crops (e.g., wheat) worldwide. Elimination of Buchnera using the antibiotic rifampicin significantly reduced the formation of winged morphs, body mass, and fecundity in S. avenae. Furthermore, the absence of this primary endosymbiont may disrupt the nutrient acquisition in aphids and alter transgenerational phenotypic expression. Similarly, both survival rate and the formation of winged morphs were substantially reduced after neonatal (<24 h old) offspring were starved for a period of time. The combined results shed light on the impact of two nutritional-based biotic factors on the phenotypic plasticity in aphids. A better understanding of the wing dimorphism in aphids will provide the theoretical basis for the prediction and integrated management of these phloem-feeding insect pests. PMID:26042046

Metabolic engineering of plant-derived (E)-β-farnesene synthase genes for a novel type of aphid-resistant genetically modified crop plants.

PubMed

Yu, Xiu-Dao; Pickett, John; Ma, You-Zhi; Bruce, Toby; Napier, Johnathan; Jones, Huw D; Xia, Lan-Qin

2012-05-01

Aphids are major agricultural pests that cause significant yield losses of crop plants each year. Excessive dependence on insecticides for long-term aphid control is undesirable because of the development of insecticide resistance, the potential negative effects on non-target organisms and environmental pollution. Transgenic crops engineered for resistance to aphids via a non-toxic mode of action could be an efficient alternative strategy. (E)-β-Farnesene (EβF) synthases catalyze the formation of EβF, which for many pest aphids is the main component of the alarm pheromone involved in the chemical communication within these species. EβF can also be synthesized by certain plants but is then normally contaminated with inhibitory compounds. Engineering of crop plants capable of synthesizing and emitting EβF could cause repulsion of aphids and also the attraction of natural enemies that use EβF as a foraging cue, thus minimizing aphid infestation. In this review, the effects of aphids on host plants, plants' defenses against aphid herbivory and the recruitment of natural enemies for aphid control in an agricultural setting are briefly introduced. Furthermore, the plant-derived EβF synthase genes cloned to date along with their potential roles in generating novel aphid resistance via genetically modified approaches are discussed. © 2012 Institute of Botany, Chinese Academy of Sciences.

Estimation of the dispersal distances of an aphid-borne virus in a patchy landscape

PubMed Central

Soubeyrand, Samuel; Dallot, Sylvie; Labonne, Gérard; Chadœuf, Joël; Jacquot, Emmanuel

2018-01-01

Characterising the spatio-temporal dynamics of pathogens in natura is key to ensuring their efficient prevention and control. However, it is notoriously difficult to estimate dispersal parameters at scales that are relevant to real epidemics. Epidemiological surveys can provide informative data, but parameter estimation can be hampered when the timing of the epidemiological events is uncertain, and in the presence of interactions between disease spread, surveillance, and control. Further complications arise from imperfect detection of disease and from the huge number of data on individual hosts arising from landscape-level surveys. Here, we present a Bayesian framework that overcomes these barriers by integrating over associated uncertainties in a model explicitly combining the processes of disease dispersal, surveillance and control. Using a novel computationally efficient approach to account for patch geometry, we demonstrate that disease dispersal distances can be estimated accurately in a patchy (i.e. fragmented) landscape when disease control is ongoing. Applying this model to data for an aphid-borne virus (Plum pox virus) surveyed for 15 years in 605 orchards, we obtain the first estimate of the distribution of flight distances of infectious aphids at the landscape scale. About 50% of aphid flights terminate beyond 90 m, which implies that most infectious aphids leaving a tree land outside the bounds of a 1-ha orchard. Moreover, long-distance flights are not rare–10% of flights exceed 1 km. By their impact on our quantitative understanding of winged aphid dispersal, these results can inform the design of management strategies for plant viruses, which are mainly aphid-borne. PMID:29708968

The Role of Natural Enemy Foraging Guilds in Controlling Cereal Aphids in Michigan Wheat

PubMed Central

Safarzoda, Shahlo; Bahlai, Christine A.; Fox, Aaron F.; Landis, Douglas A.

2014-01-01

Insect natural enemies (predators and parasitoids) provide important ecosystem services by suppressing populations of insect pests in many agricultural crops. However, the role of natural enemies against cereal aphids in Michigan winter wheat (Triticum aestivum L.) is largely unknown. The objectives of this research were to characterize the natural enemy community in wheat fields and evaluate the role of different natural enemy foraging guilds (foliar-foraging versus ground-dwelling predators) in regulating cereal aphid population growth. We investigated these objectives during the spring and summer of 2012 and 2013 in four winter wheat fields on the Michigan State University campus farm in East Lansing, Michigan. We monitored and measured the impact of natural enemies by experimentally excluding or allowing their access to wheat plants infested with Rhopalosiphum padi (L.) and Sitobion avenae (F.) (Hemiptera: Aphidae). Our results indicate that the natural enemy community in the wheat fields consisted mostly of foliar-foraging and ground-dwelling predators with relatively few parasitoids. In combination, these natural enemy groups were very effective at reducing cereal aphid populations. We also investigated the role of each natural enemy foraging guild (foliar-foraging versus ground-dwelling predators) independently. Overall, our results suggest that, in combination, natural enemies can almost completely halt early-season aphid population increase. Independently, ground-dwelling predators were more effective at suppressing cereal aphid populations than foliar-foraging predators under the conditions we studied. Our results differ from studies in Europe and the US Great Plains where foliar foraging predators and parasitoids are frequently more important cereal aphid natural enemies. PMID:25473951

Risk to native Uroleucon aphids (Hemiptera: Aphididae) from non-native lady beetles (Coleoptera: Coccinellidae)

USDA-ARS?s Scientific Manuscript database

Aphids in the genus Uroleucon Mordvilko (Hemiptera: Aphididae) are native herbivores that feed on goldenrod (Solidago spp.) and other Asteraceae in North America. The aphids are potential prey for a wide variety of natural enemies, including native and non-native species of lady beetles (Coleoptera...

Role of Soybean mosaic virus-encoded proteins in seed and aphid transmission in soybean

USDA-ARS?s Scientific Manuscript database

Soybean mosaic virus (SMV) is seed and aphid transmitted and can cause significant reductions in yield and seed quality in soybean, Glycine max. The roles in seed and aphid transmission of selected SMV-encoded proteins were investigated by constructing chimeric recombinants between SMV 413 (efficien...

The Endosymbiont Arsenophonus Is Widespread in Soybean Aphid, Aphis glycines, but Does Not Provide Protection from Parasitoids or a Fungal Pathogen

PubMed Central

Wulff, Jason A.; Buckman, Karrie A.; Wu, Kongming; Heimpel, George E.; White, Jennifer A.

2013-01-01

Aphids commonly harbor bacterial facultative symbionts that have a variety of effects upon their aphid hosts, including defense against hymenopteran parasitoids and fungal pathogens. The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is infected with the symbiont Arsenophonus sp., which has an unknown role in its aphid host. Our research goals were to document the infection frequency and diversity of the symbiont in field-collected soybean aphids, and to determine whether Arsenophonus is defending soybean aphid against natural enemies. We performed diagnostic PCR and sequenced four Arsenophonus genes in soybean aphids from their native and introduced range to estimate infection frequency and genetic diversity, and found that Arsenophonus infection is highly prevalent and genetically uniform. To evaluate the defensive role of Arsenophonus, we cured two aphid genotypes of their natural Arsenophonus infection through ampicillin microinjection, resulting in infected and uninfected isolines within the same genetic background. These isolines were subjected to parasitoid assays using a recently introduced biological control agent, Binodoxys communis [Braconidae], a naturally recruited parasitoid, Aphelinus certus [Aphelinidae], and a commercially available biological control agent, Aphidius colemani [Braconidae]. We also assayed the effect of the common aphid fungal pathogen, Pandora neoaphidis (Remaudiere & Hennebert) Humber (Entomophthorales: Entomophthoraceae), on the same aphid isolines. We did not find differences in successful parasitism for any of the parasitoid species, nor did we find differences in P. neoaphidis infection between our treatments. Our conclusion is that Arsenophonus does not defend its soybean aphid host against these major parasitoid and fungal natural enemies. PMID:23614027

Evolutionary lability of a complex life cycle in the aphid genus Brachycaudus.

PubMed

Emmanuelle, Jousselin; Gwenaelle, Genson; Armelle, Coeur d'acier

2010-09-28

Most aphid species complete their life cycle on the same set of host-plant species, but some (heteroecious species) alternate between different hosts, migrating from primary (woody) to secondary (herbaceous) host plants. The evolutionary processes behind the evolution of this complex life cycle have often been debated. One widely accepted scenario is that heteroecy evolved from monoecy on woody host plants. Several shifts towards monoecy on herbaceous plants have subsequently occurred and resulted in the radiation of aphids. Host alternation would have persisted in some cases due to developmental constraints preventing aphids from shifting their entire life cycle to herbaceous hosts (which are thought to be more favourable). According to this scenario, if aphids lose their primary host during evolution they should not regain it. The genus Brachycaudus includes species with all the types of life cycle (monoecy on woody plants, heteroecy, monoecy on herbs). We used this genus to test hypotheses concerning the evolution of life cycles in aphids. Phylogenetic investigation and character reconstruction suggest that life cycle is evolutionary labile in the genus. Though ancestral character states can be ambiguous depending on optimization methods, all analyses suggest that transitions from monoecy on herbs towards heteroecy have occurred several times. Transitions from heteroecy towards monoecy, are also likely. There have been many shifts in feeding behaviour but we found no significant correlation between life cycle changes and changes in diet. The transitions from monoecy on herbs towards heteroecy observed in this study go against a widely accepted evolutionary scenario: aphids in the genus Brachycaudus seem to be able to recapture their supposedly ancestral woody host. This suggests that the determinants of host alternation are probably not as complicated as previously thought. Definitive proofs of the lability of life cycle in Brachycaudus will necessitate

Transgenic tobacco expressing Pinellia ternata agglutinin confers enhanced resistance to aphids.

PubMed

Yao, Jianhong; Pang, Yongzhen; Qi, Huaxiong; Wan, Bingliang; Zhao, Xiuyun; Kong, Weiwen; Sun, Xiaofen; Tang, Kexuan

2003-12-01

Tobacco leaf discs were transformed with a plasmid, pBIPTA, containing the selectable marker neomycin phosphotransferase gene (nptII) and Pinellia ternata agglutinin gene (pta) via Agrobacterium tumefaciens-mediated transformation. Thirty-two independent transgenic tobacco plants were regenerated. PCR and Southern blot analyses confirmed that the pta gene had integrated into the plant genome and northern blot analysis revealed transgene expression at various levels in transgenic plants. Genetic analysis confirmed Mendelian segregation of the transgene in T1 progeny. Insect bioassays showed that transgenic plants expressing PTA inhibited significantly the growth of peach potato aphid (Myzus persicae Sulzer). This is the first report that transgenic plants expressing pta confer enhanced resistance to aphids. Our study indicates that the pta gene can be used as a supplement to the snowdrop (Galanthus nivalis) lectin gene (gna) in the control of aphids, a sap-sucking insect pest causing significant yield losses of crops.

Registration of ‘CP 09-1822’ Sugarcane

USDA-ARS?s Scientific Manuscript database

‘CP 09-1822’ (Reg. No. __; PI 686942 sugarcane (a complex hybrid of Saccharum spp.) was released in June 2016 for commercial cultivation on sand (mineral) soils in Florida. This cultivar was developed through a collaborative sugarcane cultivar development program of the USDA-ARS, the University of F...

Registration of ‘Ho 00-961’ sugarcane

USDA-ARS?s Scientific Manuscript database

‘Ho 00-961’ (Reg. No., PI) sugarcane (a complex hybrid of Saccharum officinarum L., S. spontaneum L., S. barberi Jeswiet, and S. sinense Roxb. amend. Jeswiet) was selected by the USDA-ARS Sugarcane Research Unit, and evaluated cooperatively with the Louisiana State University Agricultural Center, an...

Population Dynamics of Aphids on Cereals: Digging in the Time-Series Data to Reveal Population Regulation Caused by Temperature

PubMed Central

Brabec, Marek; Honěk, Alois; Pekár, Stano; Martinková, Zdenka

2014-01-01

Aphid populations show periodic fluctuations and many causes are attributed to their dynamic. We investigated the regulation by temperature of the aphid populations composed of Metopolophium dirhodum, Sitobion avenae, and Rhopalosiphum padi on winter wheat using a 24 years long time series data. We computed the sum of daily temperatures above 5°C, the threshold temperature for aphid development, and the sum of daily temperatures within the [0(threshold for wheat development),5] °C interval. Applying Generalised Additive Model framework we tested influences of temperature history expressed via degree days before the start of the aphid immigration on the length of their occurrence. We aimed to estimate the magnitude and direction of this influence, and how far to the past before the start of the aphid season the temperature effect goes and then identify processes responsible for the effect. We fitted four models that differed in the way of correcting for abundance in the previous year and in specification of temperature effects. Abundance in the previous year did not affect the length of period of aphid population growth on wheat. The temperature effect on the period length increased up to 123 days before the start of the current season, i.e. when wheat completed vernalization. Increased sum of daily temperatures above 5°C and the sum of daily temperatures within the [0,5] °C interval both shortened the length of period of aphid population growth. Stronger effect of the latter suggests that wheat can escape from aphid attacks if during winter temperatures range from 0 to 5°C. The temperature influence was not homogeneous in time. The strongest effect of past temperature was about 50 to 80 and 90 to 110 days before the beginning of the current aphid season indicating important role of termination of aphid egg dormancy and egg hatching. PMID:25184219

Nutrition versus defense: Why Myzus persicae (green peach aphid) prefers and performs better on young leaves of cabbage

PubMed Central

Cao, He-He; Zhang, Zhan-Feng; Wang, Xiao-Feng

2018-01-01

Plant leaves of different ages differ in nutrients and toxic metabolites and thus exhibit various resistance levels against insect herbivores. However, little is known about the influence of leaf ontogeny on plant resistance to phloem-feeding insects. In this study, we found that the green peach aphid, Myzus persicae, preferred to settle on young cabbage leaves compared with mature or old leaves, although young leaves contained the highest concentration of glucosinolates. Furthermore, aphids feeding on young leaves had higher levels of glucosinolates in their body, but aphids performed better on young leaves in terms of body weight and population growth. Phloem sap of young leaves had higher amino acid:sugar molar ratio than mature leaves, and aphids feeding on young leaves showed two times longer phloem feeding time and five times more honeydew excretion than on other leaves. These results indicate that aphids acquired the highest amount of nutrients and defensive metabolites when feeding on young cabbage leaves that are strong natural plant sinks. Accordingly, we propose that aphids generally prefer to obtain more nutrition rather than avoiding host plant defense, and total amount of nutrition that aphids could obtain is significantly influenced by leaf ontogeny or source-sink status of feeding sites. PMID:29684073

Aphids preserved in propylene glycol can be used for reverse transcription-polymerase chain reaction detection of Potato virus Y.

PubMed

Nie, Xianzhou; Pelletier, Yvan; Mason, Nicola; Dilworth, Andrea; Giguère, Marie-Andrée

2011-08-01

The effectiveness of propylene glycol on the retention of RNA target of Potato virus Y (PVY), an aphid stylet-borne virus, in Myzus persicae was investigated in comparison to ethanol and liquid nitrogen/-80°C. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the PVY targets from the propylene glycol/ethanol/liquid nitrogen preserved single aphids after a 5min acquisition period from infected potato plants. In the liquid nitrogen/-80°C and 70% ethanol treatments, 55.6% and 38.8% aphids tested PVY-positive, respectively. In the 0-75% propylene glycol treatments, 12.2-44.7% aphids tested PVY-positive. The lowest detection rate was in the 0% (positive rate, 15.2%) and the 10% propylene glycol (positive rate, 12.2%). As the propylene glycol concentration increased to 25%, 29.8% aphids tested positive. A high PVY-positive rate was also found in 35-75% propylene glycol treatments at 44.7% (35% propylene glycol), 36.7% (50% propylene glycol) and 34.8% (75% propylene glycol), which is comparable to the rate shown in 70% ethanol. No significant difference in the positive detection rate was observed in aphids preserved in 50% propylene glycol at room temperature for 2, 4 and 10 days. These results demonstrate that propylene glycol at 25-75% can retain PVY targets effectively in aphids for an extended time period, and thus can be used in aphid traps to preserve viruliferous aphids for later RT-PCR detection of PVY. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

Characterization and genetics of multiple soybean aphid biotype resistance in five soybean plant introductions

USDA-ARS?s Scientific Manuscript database

Soybean aphid (Aphis glycines Matsumura) is the most important soybean [Glycine max (L.) Merr.] insect pest in the USA. The objectives of this study were to characterize the resistance expressed in the five plant introductions (PIs) to four soybean aphid biotypes, determine the mode of resistance in...

Geographic distribution of soybean aphid biotypes in USA and Canada during 2008 - 2010

USDA-ARS?s Scientific Manuscript database

The soybean aphid (Aphis glycines Matsumura) is a native pest of soybean in eastern Asia and was detected on soybeans in North America in 2000. In 2004, the soybean variety ‘“Dowling”’ was described to be resistant to soybean aphids with the Rag1 gene for resistance. In 2006, a virulent biotype of s...

Registration of ‘CP 09-1430’ Sugarcane

USDA-ARS?s Scientific Manuscript database

‘CP 09-1430’ (Reg. No. ; PI 686940 sugarcane (a complex hybrid of Saccharum spp.) was developed and released (6 Jun. 2016) through cooperative research conducted by the USDA-ARS Sugarcane Field Station , Canal Point, the University of Florida, and the Florida Sugar Cane League, Inc. for use on ...

Sugarcane Genotype Selection for Sand Soils in Florida

USDA-ARS?s Scientific Manuscript database

Selection of high yielding sugarcane (Saccharum spp.) genotypes for organic (muck) soils in Florida has been more successful than for sand soils. The purpose of this study was to compare the performance of 31 sugarcane genotypes on sand soils with and without mill mud added at the rate of 1510 cubic...

Early changes in arbuscular mycorrhiza development in sugarcane under two harvest management systems.

PubMed

de Azevedo, Lucas Carvalho Basilio; Stürmer, Sidney Luiz; Lambais, Marcio Rodrigues

2014-01-01

Sugarcane (Saccharum spp.) is grown on over 8 million ha in Brazil and is used to produce ethanol and sugar. Some sugarcane fields are burned to facilitate harvesting, which can affect the soil microbial community. However, whether sugarcane pre-harvest burning affects the community of arbuscular mycorrhizal fungi (AMF) and symbioses development is not known. In this study, we investigated the early impacts of harvest management on AMF spore communities and root colonization in three sugarcane varieties, under two harvest management systems (no-burning and pre-harvest burning). Soil and root samples were collected in the field after the first harvest of sugarcane varieties SP813250, SP801842, and RB72454, and AMF species were identified based on spore morphology. Diversity indices were determined based on spore populations and root colonization determined as an indicator of symbioses development. Based on the diversity indices, spore number and species occurrence in soil, no significant differences were observed among the AMF communities, regardless of harvest management type, sugarcane variety or interactions between harvest management type and sugarcane variety. However, mycorrhiza development was stimulated in sugarcane under the no-burning management system. Our data suggest that the sugarcane harvest management system may cause early changes in arbuscular mycorrhiza development.

Early changes in arbuscular mycorrhiza development in sugarcane under two harvest management systems

PubMed Central

de Azevedo, Lucas Carvalho Basilio; Stürmer, Sidney Luiz; Lambais, Marcio Rodrigues

2014-01-01

Sugarcane (Saccharum spp.) is grown on over 8 million ha in Brazil and is used to produce ethanol and sugar. Some sugarcane fields are burned to facilitate harvesting, which can affect the soil microbial community. However, whether sugarcane pre-harvest burning affects the community of arbuscular mycorrhizal fungi (AMF) and symbioses development is not known. In this study, we investigated the early impacts of harvest management on AMF spore communities and root colonization in three sugarcane varieties, under two harvest management systems (no-burning and pre-harvest burning). Soil and root samples were collected in the field after the first harvest of sugarcane varieties SP813250, SP801842, and RB72454, and AMF species were identified based on spore morphology. Diversity indices were determined based on spore populations and root colonization determined as an indicator of symbioses development. Based on the diversity indices, spore number and species occurrence in soil, no significant differences were observed among the AMF communities, regardless of harvest management type, sugarcane variety or interactions between harvest management type and sugarcane variety. However, mycorrhiza development was stimulated in sugarcane under the no-burning management system. Our data suggest that the sugarcane harvest management system may cause early changes in arbuscular mycorrhiza development. PMID:25477936

PCDD AND PCDF EMISSIONS FROM SIMULATED SUGARCANE FIELD BURNING

EPA Science Inventory

The emissions from simulated sugarcane field burns were sampled and analyzed for polychlorinated dibenzodioxins and dibenzofurans (PCDDs and PCDFs). Sugarcane leaves from Hawaii and Florida were burned in a manner simulating the natural physical dimensions and biomass density fou...

The price of protection: a defensive endosymbiont impairs nymph growth in the bird cherry-oat aphid, Rhopalosiphum padi.

PubMed

Leybourne, Daniel J; Bos, Jorunn I B; Valentine, Tracy A; Karley, Alison J

2018-05-24

Bacterial endosymbionts have enabled aphids to adapt to a range of stressors, but their effects in many aphid species remain to be established. The bird cherry-oat aphid, Rhopalosiphum padi (Linnaeus), is an important pest of cereals worldwide and has been reported to form symbiotic associations with Serratia symbiotica and Sitobion miscanthi L-type Symbiont endobacteria, although the resulting aphid phenotype has not been described. This study presents the first report of R. padi infection with the facultative bacterial endosymbiont Hamiltonella defensa. Individuals of R. padi were sampled from populations in Eastern Scotland, UK, and shown to represent seven R. padi genotypes based on the size of polymorphic microsatellite markers; two of these genotypes harboured H. defensa. In parasitism assays, survival of H. defensa-infected nymphs following attack by the parasitoid wasp Aphidius colemani (Viereck) was five-fold higher than for uninfected nymphs. Aphid genotype was a major determinant of aphid performance on two Hordeum species, a modern cultivar of barley H. vulgaris and a wild relative H. spontaneum, although aphids infected with H. defensa showed 16% lower nymph mass gain on the partially-resistant wild relative compared with uninfected individuals. These findings suggest that deploying resistance traits in barley will favour the fittest R. padi genotypes, but symbiont-infected individuals will be favoured when parasitoids are abundant, although these aphids will not achieve optimal performance on a poor quality host plant. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Indirect multi-trophic interactions mediated by induced plant resistance: impact of caterpillar feeding on aphid parasitoids

PubMed Central

Hagenbucher, Steffen; Wäckers, Felix L.; Romeis, Jörg

2014-01-01

Cotton produces insecticidal terpenoids that are induced by tissue-feeding herbivores. Damage by Heliothis virescens caterpillars increases the terpenoid content, which reduces the abundance of aphids. This effect is not evident in Bt-transgenic cotton, which is resistant to H. virescens. We determined whether induction of terpenoids by caterpillars influences the host quality of Aphis gossypii for the parasitoid Lysiphlebus testaceipes and whether this interaction is influenced by Bt cotton. The exposure of parasitoids to terpenoids was determined by quantifying terpenoids in the aphids. We detected several terpenoids in aphids and found a positive relationship between their concentrations in plants and aphids. When L. testaceipes was allowed to parasitize aphids on Bt and non-Bt cotton that was infested or uninfested with H. virescens, fewer parasitoid mummies were found on infested non-Bt than on Bt cotton. Important parasitoid life-table parameters, however, were not influenced by induced resistance following H. virescens infestation, or the Bt trait. Our study provides an example of a tritrophic indirect interaction web, where organisms are indirectly linked through changes in plant metabolites. PMID:24522627

Biology and Fertility Life Table of the Green Aphid Chaetosiphon Fragaefolli on Strawberry Cultivars

PubMed Central

Bernardi, Daniel; Garcia, Mauro Silveira; Botton, Marcos; Nava, Dori Edson

2012-01-01

Our objective was to study the biology and develop a fertility life table for the aphid Chaetosiphon fragaefolli (Cockerell) (Hemiptera: Aphididae) on leaves of strawberry, Fragaria × ananassa, Duchesne ex Rozier (Rosales: Rosaceae), of the cultivars Albion, Aromas, Camarosa, Camino Real, Diamante, Earlibrite, and Saborosa. This study was conducted under controlled conditions: 25 ± 1 °C, 70 ± 10% RH, and 12:12 L:D . Arenas were set up consisting of leaves inside Petri dishes containing 3% agar. Female aphids obtained after the last nymphal ecdysis were individually placed in arenas for 24 hours. The following biological parameters were evaluated: duration and survival of the nymph stage and of the life cycle (nymph-nymph), daily and total fecundity, and adult longevity. The aphids completed their biological cycle on all of the cultivars. The shortest durations (in days) of the nymphal stage were on the cultivars Camino Real and Camarosa (8.67 and 8.74 days, respectively), and the longest was on Aromas (11.12 days). The lowest survival was on cultivar Aromas (51%) and the highest on Saborosa (96%). When the time to development to the adult stage was compared, the aphids developed fastest (14.63 days) and survival was highest (96%) on cultivar Saborosa. Aphids reared on cultivar Aromas leaves had the longest pre—reproductive period (8.74 days), the greatest longevity (26.88 days), and the longest duration of the life cycle (19.76 days). Based on the fertility life table, cultivars Camarosa and Saborosa were the most favorable for development of C. fragaefolli, while Albion and Aromas were the most inadequate for aphid development. PMID:22958325

Monitoring Freeze Injury and Evaluating Losingto Sugar-Cane Using RS and GPS

NASA Astrophysics Data System (ADS)

Tan, Zongkun; Ding, Meihua; Wang, Longhe; Yang, Xin; Ou, Zhaorong

From Jan 12th to Feb 12th 2008, the most severity cold chilling and freeze injury weather took place during the last 50 years in the southern of China.Sugar-cane was suffered injury severity. However, the losing of sugar-cane which it was aroused by thisweather disaster had not been exactitude evaluated till on Apr 1st, 2008. It was not only affected the sugar-cane ordinary harvesting and crushing, but also affected reserving sugar-cane seed for planting. Freeze injury is common disaster for sugar-cane in southern of China and monitoring freeze injury using RS and GIS are of great economic significance but little research work about it has been done in China Freeze injuring is not only related to crop growth stage and the cold air intension from northern to southern and weather types, but also consanguineous related to land form and physiognomy and geographical latitude and height above sea level etc and crop planting spatial distribution. The case study of Guangxi province which is the biggest region of sugar-cane planting in China in this paper, the values of sugar-cane NDVI among the freeze injury occur former and after in early 2008 and without freeze injury occur in the same term 2007 were analyzed and compared based on the sugar-cane planting spatial distribution information which were carried out by using multi-phase EOS/MODIS data. The result showed that it was not only commendably reflected the spatial distribution of freeze injury but also reflected the sugarcane suffered from degree using the values of sugar-cane NDVIof freeze injury occur former and after. The field sample investigation data of using GPS was integrated with the NDVI, the evaluation of region sugar-cane suffer from freeze injury losing could quickly and exactly realize.

7 CFR 1435.311 - Proportionate shares for sugarcane producers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS SUGAR PROGRAM Flexible Marketing Allotments For Sugar § 1435.311 Proportionate shares for sugarcane producers. (a... sugarcane farms. (b) CCC will determine whether Louisiana sugar production, in the absence of proportionate...

7 CFR 1435.311 - Proportionate shares for sugarcane producers.

Code of Federal Regulations, 2014 CFR

2014-01-01

... CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS SUGAR PROGRAM Flexible Marketing Allotments For Sugar § 1435.311 Proportionate shares for sugarcane producers. (a... sugarcane farms. (b) CCC will determine whether Louisiana sugar production, in the absence of proportionate...

7 CFR 1435.311 - Proportionate shares for sugarcane producers.

Code of Federal Regulations, 2013 CFR

2013-01-01

... CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS SUGAR PROGRAM Flexible Marketing Allotments For Sugar § 1435.311 Proportionate shares for sugarcane producers. (a... sugarcane farms. (b) CCC will determine whether Louisiana sugar production, in the absence of proportionate...

7 CFR 1435.311 - Proportionate shares for sugarcane producers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS SUGAR PROGRAM Flexible Marketing Allotments For Sugar § 1435.311 Proportionate shares for sugarcane producers. (a... sugarcane farms. (b) CCC will determine whether Louisiana sugar production, in the absence of proportionate...

7 CFR 1435.311 - Proportionate shares for sugarcane producers.

Code of Federal Regulations, 2011 CFR

2011-01-01

... CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS SUGAR PROGRAM Flexible Marketing Allotments For Sugar § 1435.311 Proportionate shares for sugarcane producers. (a... sugarcane farms. (b) CCC will determine whether Louisiana sugar production, in the absence of proportionate...

Expression profiling of selected glutathione transferase genes in Zea mays (L.) seedlings infested with cereal aphids.

PubMed

Sytykiewicz, Hubert; Chrzanowski, Grzegorz; Czerniewicz, Paweł; Sprawka, Iwona; Łukasik, Iwona; Goławska, Sylwia; Sempruch, Cezary

2014-01-01

The purpose of this report was to evaluate the expression patterns of selected glutathione transferase genes (gst1, gst18, gst23 and gst24) in the tissues of two maize (Zea mays L.) varieties (relatively resistant Ambrozja and susceptible Tasty Sweet) that were colonized with oligophagous bird cherry-oat aphid (Rhopalosiphum padi L.) or monophagous grain aphid (Sitobion avenae L.). Simultaneously, insect-triggered generation of superoxide anion radicals (O2•-) in infested Z. mays plants was monitored. Quantified parameters were measured at 1, 2, 4, 8, 24, 48 and 72 h post-initial aphid infestation (hpi) in relation to the non-infested control seedlings. Significant increases in gst transcript amounts were recorded in aphid-stressed plants in comparison to the control seedlings. Maximal enhancement in the expression of the gst genes in aphid-attacked maize plants was found at 8 hpi (gst23) or 24 hpi (gst1, gst18 and gst24) compared to the control. Investigated Z. mays cultivars formed excessive superoxide anion radicals in response to insect treatments, and the highest overproduction of O2•- was noted 4 or 8 h after infestation, depending on the aphid treatment and maize genotype. Importantly, the Ambrozja variety could be characterized as having more profound increments in the levels of gst transcript abundance and O2•- generation in comparison with the Tasty Sweet genotype.

Erwinia iniecta sp. nov., isolated from Russian wheat aphid (Diuraphis noxia).

PubMed

Campillo, Tony; Luna, Emily; Portier, Perrine; Fischer-Le Saux, Marion; Lapitan, Nora; Tisserat, Ned A; Leach, Jan E

2015-10-01

Short, Gram-negative-staining, rod-shaped bacteria were isolated from crushed bodies of Russian wheat aphid [Diuraphis noxia (Kurdjumov)] and artificial diets after Russian wheat aphid feeding. Based on multilocus sequence analysis involving the 16S rRNA, atpD, infB, gyrB and rpoB genes, these bacterial isolates constitute a novel clade in the genus Erwinia, and were most closely related to Erwinia toletana. Representative distinct strains within this clade were used for comparisons with related species of Erwinia. Phenotypic comparisons using four distinct strains and average nucleotide identity (ANI) measurements using two distinct draft genomes revealed that these strains form a novel species within the genus Erwinia. The name Erwinia iniecta sp. nov. is proposed, and strain B120T ( = CFBP 8182T = NCCB 100485T) was designated the type strain. Erwinia iniecta sp. nov. was not pathogenic to plants. However, virulence to the Russian wheat aphid was observed.

Dynamic Maize Responses to Aphid Feeding Are Revealed by a Time Series of Transcriptomic and Metabolomic Assays1[OPEN

PubMed Central

Tzin, Vered; Fernandez-Pozo, Noe; Richter, Annett; Schmelz, Eric A.; Schoettner, Matthias; Schäfer, Martin; Ahern, Kevin R.; Meihls, Lisa N.; Kaur, Harleen; Huffaker, Alisa; Mori, Naoki; Degenhardt, Joerg; Mueller, Lukas A.; Jander, Georg

2015-01-01

As a response to insect attack, maize (Zea mays) has inducible defenses that involve large changes in gene expression and metabolism. Piercing/sucking insects such as corn leaf aphid (Rhopalosiphum maidis) cause direct damage by acquiring phloem nutrients as well as indirect damage through the transmission of plant viruses. To elucidate the metabolic processes and gene expression changes involved in maize responses to aphid attack, leaves of inbred line B73 were infested with corn leaf aphids for 2 to 96 h. Analysis of infested maize leaves showed two distinct response phases, with the most significant transcriptional and metabolic changes occurring in the first few hours after the initiation of aphid feeding. After 4 d, both gene expression and metabolite profiles of aphid-infested maize reverted to being more similar to those of control plants. Although there was a predominant effect of salicylic acid regulation, gene expression changes also indicated prolonged induction of oxylipins, although not necessarily jasmonic acid, in aphid-infested maize. The role of specific metabolic pathways was confirmed using Dissociator transposon insertions in maize inbred line W22. Mutations in three benzoxazinoid biosynthesis genes, Bx1, Bx2, and Bx6, increased aphid reproduction. In contrast, progeny production was greatly decreased by a transposon insertion in the single W22 homolog of the previously uncharacterized B73 terpene synthases TPS2 and TPS3. Together, these results show that maize leaves shift to implementation of physical and chemical defenses within hours after the initiation of aphid feeding and that the production of specific metabolites can have major effects in maize-aphid interactions. PMID:26378100

Turning in mid-air allows aphids that flee the plant to avoid reaching the risky ground.

PubMed

Meresman, Yonatan; Ben-Ari, Matan; Inbar, Moshe

2017-09-01

When forced to drop from the plant, flightless arboreal insects can avoid reaching the risky ground by maneuvering their body through the air. When wingless pea aphids (Acyrthosiphon pisum) are threatened by natural enemies, they often drop off their host plant while assuming a stereotypic posture that rotates them in mid-air, aligning them with their feet pointing downwards. This position may increase their chances of re-clinging onto lower plant parts and avoid facing the dangers on the ground, although its effectiveness in realistic field conditions has not been tested. We performed both laboratory and outdoor experiments, in which we dropped aphids upon host plants to quantify clinging success in plants with different characteristics such as height and leaf size. Live aphids had twofold higher clinging rates than dead ones, indicating that clinging success is indeed affected by the active aerial-righting of dropping aphids. The ability to cling was positively dependent on the plants' foliage cover as viewed in vertical direction from above. Therefore, we released aphids in commercial alfalfa (Medicago sativa) fields with varying plant heights and foliage cover and induced them to drop. Most (up to 75%) of the aphids avoided reaching the ground in taller plants (65 cm), and 17% in shorter plants (21 cm), demonstrating the efficiency of the aphids' response in averting risks: both those of an approaching enemy on the plant and the plethora of new risks on the ground. Evidently, even in complex field environment, the aerial-righting mechanism can substantially reduce the possible risks following escape from a predator. © 2017 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Up-regulation of abscisic acid signaling pathway facilitates aphid xylem absorption and osmoregulation under drought stress.

PubMed

Guo, Huijuan; Sun, Yucheng; Peng, Xinhong; Wang, Qinyang; Harris, Marvin; Ge, Feng

2016-02-01

The activation of the abscisic acid (ABA) signaling pathway reduces water loss from plants challenged by drought stress. The effect of drought-induced ABA signaling on the defense and nutrition allocation of plants is largely unknown. We postulated that these changes can affect herbivorous insects. We studied the effects of drought on different feeding stages of pea aphids in the wild-type A17 of Medicago truncatula and ABA signaling pathway mutant sta-1. We examined the impact of drought on plant water status, induced plant defense signaling via the abscisic acid (ABA), jasmonic acid (JA), and salicylic acid (SA) pathways, and on the host nutritional quality in terms of leaf free amino acid content. During the penetration phase of aphid feeding, drought decreased epidermis/mesophyll resistance but increased mesophyll/phloem resistance of A17 but not sta-1 plants. Quantification of transcripts associated with ABA, JA and SA signaling indicated that the drought-induced up-regulation of ABA signaling decreased the SA-dependent defense but increased the JA-dependent defense in A17 plants. During the phloem-feeding phase, drought had little effect on the amino acid concentrations and the associated aphid phloem-feeding parameters in both plant genotypes. In the xylem absorption stage, drought decreased xylem absorption time of aphids in both genotypes because of decreased water potential. Nevertheless, the activation of the ABA signaling pathway increased water-use efficiency of A17 plants by decreasing the stomatal aperture and transpiration rate. In contrast, the water potential of sta-1 plants (unable to close stomata) was too low to support xylem absorption activity of aphids; the aphids on sta-1 plants had the highest hemolymph osmolarity and lowest abundance under drought conditions. Taken together this study illustrates the significance of cross-talk between biotic-abiotic signaling pathways in plant-aphid interaction, and reveals the mechanisms leading to alter

Up-regulation of abscisic acid signaling pathway facilitates aphid xylem absorption and osmoregulation under drought stress

PubMed Central

Guo, Huijuan; Sun, Yucheng; Peng, Xinhong; Wang, Qinyang; Harris, Marvin; Ge, Feng

2016-01-01

The activation of the abscisic acid (ABA) signaling pathway reduces water loss from plants challenged by drought stress. The effect of drought-induced ABA signaling on the defense and nutrition allocation of plants is largely unknown. We postulated that these changes can affect herbivorous insects. We studied the effects of drought on different feeding stages of pea aphids in the wild-type A17 of Medicago truncatula and ABA signaling pathway mutant sta-1. We examined the impact of drought on plant water status, induced plant defense signaling via the abscisic acid (ABA), jasmonic acid (JA), and salicylic acid (SA) pathways, and on the host nutritional quality in terms of leaf free amino acid content. During the penetration phase of aphid feeding, drought decreased epidermis/mesophyll resistance but increased mesophyll/phloem resistance of A17 but not sta-1 plants. Quantification of transcripts associated with ABA, JA and SA signaling indicated that the drought-induced up-regulation of ABA signaling decreased the SA-dependent defense but increased the JA-dependent defense in A17 plants. During the phloem-feeding phase, drought had little effect on the amino acid concentrations and the associated aphid phloem-feeding parameters in both plant genotypes. In the xylem absorption stage, drought decreased xylem absorption time of aphids in both genotypes because of decreased water potential. Nevertheless, the activation of the ABA signaling pathway increased water-use efficiency of A17 plants by decreasing the stomatal aperture and transpiration rate. In contrast, the water potential of sta-1 plants (unable to close stomata) was too low to support xylem absorption activity of aphids; the aphids on sta-1 plants had the highest hemolymph osmolarity and lowest abundance under drought conditions. Taken together this study illustrates the significance of cross-talk between biotic-abiotic signaling pathways in plant-aphid interaction, and reveals the mechanisms leading to alter

Brevicoryne brassicae aphids interfere with transcriptome responses of Arabidopsis thaliana to feeding by Plutella xylostella caterpillars in a density-dependent manner.

PubMed

Kroes, Anneke; Broekgaarden, Colette; Castellanos Uribe, Marcos; May, Sean; van Loon, Joop J A; Dicke, Marcel

2017-01-01

Plants are commonly attacked by multiple herbivorous species. Yet, little is known about transcriptional patterns underlying plant responses to multiple insect attackers feeding simultaneously. Here, we assessed transcriptomic responses of Arabidopsis thaliana plants to simultaneous feeding by Plutella xylostella caterpillars and Brevicoryne brassicae aphids in comparison to plants infested by P. xylostella caterpillars alone, using microarray analysis. We particularly investigated how aphid feeding interferes with the transcriptomic response to P. xylostella caterpillars and whether this interference is dependent on aphid density and time since aphid attack. Various JA-responsive genes were up-regulated in response to feeding by P. xylostella caterpillars. The additional presence of aphids, both at low and high densities, clearly affected the transcriptional plant response to caterpillars. Interestingly, some important modulators of plant defense signalling, including WRKY transcription factor genes and ABA-dependent genes, were differentially induced in response to simultaneous aphid feeding at low or high density compared with responses to P. xylostella caterpillars feeding alone. Furthermore, aphids affected the P. xylostella-induced transcriptomic response in a density-dependent manner, which caused an acceleration in plant response against dual insect attack at high aphid density compared to dual insect attack at low aphid density. In conclusion, our study provides evidence that aphids influence the caterpillar-induced transcriptional response of A. thaliana in a density-dependent manner. It highlights the importance of addressing insect density to understand how plant responses to single attackers interfere with responses to other attackers and thus underlines the importance of the dynamics of transcriptional plant responses to multiple herbivory.

Fine mapping of the soybean aphid resistance genes Rag6 and Rag3c from glycine soja 85-32

USDA-ARS?s Scientific Manuscript database

The soybean aphid, an invasive species, has significantly threatened soybean production in North America since 2001. Host-plant resistance is known as an ideal management of aphids. Two novel aphid-resistant loci, Rag6 and Rag3c, from the Glycine soja accession 85-32, were previously detected in a 1...

Loss of Function of FATTY ACID DESATURASE7 in Tomato Enhances Basal Aphid Resistance in a Salicylate-Dependent Manner1[W][OA

PubMed Central

Avila, Carlos A.; Arévalo-Soliz, Lirio M.; Jia, Lingling; Navarre, Duroy A.; Chen, Zhaorigetu; Howe, Gregg A.; Meng, Qing-Wei; Smith, Jonathon E.; Goggin, Fiona L.

2012-01-01

We report here that disruption of function of the ω-3 FATTY ACID DESATURASE7 (FAD7) enhances plant defenses against aphids. The suppressor of prosystemin-mediated responses2 (spr2) mutation in tomato (Solanum lycopersicum), which eliminates the function of FAD7, reduces the settling behavior, survival, and fecundity of the potato aphid (Macrosiphum euphorbiae). Likewise, the antisense suppression of LeFAD7 expression in wild-type tomato plants reduces aphid infestations. Aphid resistance in the spr2 mutant is associated with enhanced levels of salicylic acid (SA) and mRNA encoding the pathogenesis-related protein P4. Introduction of the Naphthalene/salicylate hydroxylase transgene, which suppresses SA accumulation, restores wild-type levels of aphid susceptibility to spr2. Resistance in spr2 is also lost when we utilize virus-induced gene silencing to suppress the expression of NONEXPRESSOR OF PATHOGENESIS-RELATED PROTEINS1 (NPR1), a positive regulator of many SA-dependent defenses. These results indicate that FAD7 suppresses defenses against aphids that are mediated through SA and NPR1. Although loss of function of FAD7 also inhibits the synthesis of jasmonate (JA), the effects of this desaturase on aphid resistance are not dependent on JA; other mutants impaired in JA synthesis (acx1) or perception (jai1-1) show wild-type levels of aphid susceptibility, and spr2 retains aphid resistance when treated with methyl jasmonate. Thus, FAD7 may influence JA-dependent defenses against chewing insects and SA-dependent defenses against aphids through independent effects on JA synthesis and SA signaling. The Arabidopsis (Arabidopsis thaliana) mutants Atfad7-2 and Atfad7-1fad8 also show enhanced resistance to the green peach aphid (Myzus persicae) compared with wild-type controls, indicating that FAD7 influences plant-aphid interactions in at least two plant families. PMID:22291202

Soil Quality Indexing Strategies for Evaluating Sugarcane Expansion in Brazil

PubMed Central

Cherubin, Maurício R.; Karlen, Douglas L.; Cerri, Carlos E. P.; Franco, André L. C.; Tormena, Cássio A.; Davies, Christian A.; Cerri, Carlos C.

2016-01-01

Increasing demand for biofuel has intensified land-use change (LUC) for sugarcane (Saccharum officinarum) expansion in Brazil. Assessments of soil quality (SQ) response to this LUC are essential for quantifying and monitoring sustainability of sugarcane production over time. Since there is not a universal methodology for assessing SQ, we conducted a field-study at three sites within the largest sugarcane-producing region of Brazil to develop a SQ index (SQI). The most common LUC scenario (i.e., native vegetation to pasture to sugarcane) was evaluated using six SQI strategies with varying complexities. Thirty eight soil indicators were included in the total dataset. Two minimum datasets were selected: one using principal component analysis (7 indicators) and the other based on expert opinion (5 indicators). Non-linear scoring curves were used to interpret the indicator values. Weighted and non-weighted additive methods were used to combine individual indicator scores into an overall SQI. Long-term conversion from native vegetation to extensive pasture significantly decreased overall SQ. In contrast, conversion from pasture to sugarcane had no significant impact on overall SQ at the regional scale, but site-specific responses were found. In general, sugarcane production improved chemical attributes (i.e., higher macronutrient levels and lower soil acidity); however it has negative effects on physical and biological attributes (i.e., higher soil compaction and structural degradation as well as lower soil organic carbon (SOC), abundance and diversity of macrofauna and microbial activity). Overall, we found that simple, user-friendly strategies were as effective as more complex ones for identifying SQ changes. Therefore, as a protocol for SQ assessments in Brazilian sugarcane areas, we recommend using a small number of indicators (e.g., pH, P, K, Visual Evaluation of Soil Structure -VESS scores and SOC concentration) and proportional weighting to reflect chemical

Soil Quality Indexing Strategies for Evaluating Sugarcane Expansion in Brazil.

PubMed

Cherubin, Maurício R; Karlen, Douglas L; Cerri, Carlos E P; Franco, André L C; Tormena, Cássio A; Davies, Christian A; Cerri, Carlos C

2016-01-01

Increasing demand for biofuel has intensified land-use change (LUC) for sugarcane (Saccharum officinarum) expansion in Brazil. Assessments of soil quality (SQ) response to this LUC are essential for quantifying and monitoring sustainability of sugarcane production over time. Since there is not a universal methodology for assessing SQ, we conducted a field-study at three sites within the largest sugarcane-producing region of Brazil to develop a SQ index (SQI). The most common LUC scenario (i.e., native vegetation to pasture to sugarcane) was evaluated using six SQI strategies with varying complexities. Thirty eight soil indicators were included in the total dataset. Two minimum datasets were selected: one using principal component analysis (7 indicators) and the other based on expert opinion (5 indicators). Non-linear scoring curves were used to interpret the indicator values. Weighted and non-weighted additive methods were used to combine individual indicator scores into an overall SQI. Long-term conversion from native vegetation to extensive pasture significantly decreased overall SQ. In contrast, conversion from pasture to sugarcane had no significant impact on overall SQ at the regional scale, but site-specific responses were found. In general, sugarcane production improved chemical attributes (i.e., higher macronutrient levels and lower soil acidity); however it has negative effects on physical and biological attributes (i.e., higher soil compaction and structural degradation as well as lower soil organic carbon (SOC), abundance and diversity of macrofauna and microbial activity). Overall, we found that simple, user-friendly strategies were as effective as more complex ones for identifying SQ changes. Therefore, as a protocol for SQ assessments in Brazilian sugarcane areas, we recommend using a small number of indicators (e.g., pH, P, K, Visual Evaluation of Soil Structure -VESS scores and SOC concentration) and proportional weighting to reflect chemical

Effects of imidacloprid and clothianidin seed treatments on wheat aphids and their natural enemies on winter wheat.

PubMed

Zhang, Peng; Zhang, Xuefeng; Zhao, Yunhe; Wei, Yan; Mu, Wei; Liu, Feng

2016-06-01

Wheat aphid (Hemiptera: Aphididae) is one of the major pests of winter wheat and has posed a significant threat to winter wheat production in China. Although neonicotinoid insecticidal seed treatments have been suggested to be a control method, the season-long efficacy on pests and the impact on their natural enemies are still uncertain. Experiments were conducted to determine the efficacy of imidacloprid and clothianidin on the control of aphids, the number of their natural enemies and the emergence rate and yield of wheat during 2011-2014. Imidacloprid and clothianidin seed treatments had no effect on the emergence rate of winter wheat and could prevent yield losses and wheat aphid infestations throughout the winter wheat growing season. Furthermore, their active ingredients were detected in winter wheat leaves up to 200 days after sowing. Imidacloprid and clothianidin seed treatments had no adverse effects on ladybirds, hoverflies or parasitoids, and instead increased the spider-aphid ratios. Wheat seeds treated with imidacloprid and clothianidin were effective against wheat aphids throughout the winter wheat growing season and reduced the yield loss under field conditions. Imidacloprid and clothianidin seed treatments may be an important component of the integrated management of wheat aphids on winter wheat. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Frost Damage Detection in Sugarcane Crop Using Modis Images and Srtm Data

NASA Astrophysics Data System (ADS)

Rudorff, B.; Alves de Aguiar, D.; Adami, M.

2011-12-01

Brazil is the largest world producer of sugarcane which is used to produce almost equal proportions of either sugar (food) or ethanol (biofuel). In recent years sugarcane crop production has increased fast to meet the growing market demand for sugar and ethanol. This increase has been mainly due to expansion in crop area, but sugarcane production is also subjected to several factors that influence both the agricultural crop yield (tons of stalks/ha) and the industrial yield (kg of sugar/ton of stalks). Sugarcane is a semi-perennial crop that experiences major growth during spring and summer seasons with large demands for water and high temperatures to produce good stalk formation (crop yield). The harvest is performed mainly during fall and winter seasons when water availability and temperature should be low in order to accumulate sucrose in the stalks (industrial yield). These favorable climatic conditions for sugarcane crop are found in several regions in Brazil, particularly in São Paulo state, which is the major sugarcane producer in Brazil being responsible for almost 60% of its production. Despite the favorable climate in São Paulo state there is a certain probability of frost occurrence from time to time that has a negative impact on sugarcane crop, particularly on industrial yield, reducing the amount of sugar in the stalks; having consequences on price increase and product shortage. To evaluate the impact of frost on sugarcane crop, in the field, on a state level, is not a trivial task; however, this information is relevant due to its direct impact on the consumer market. Remote sensing images allow a synoptic view and present great potential to monitor large sugarcane plantations as has been done since 2003 in São Paulo state by the Canasat Project with Landsat type images (http://www.dsr.inpe.br/laf/canasat/en/). Images acquired from sensors with high temporal resolution such as MODIS (Moderate-Resolution Imaging Spectroradiometer) present the

Field evaluation of Bt cotton crop impact on nontarget pests: cotton aphid and boll weevil.

PubMed

Sujii, E R; Togni, P H B; de A Ribeiro, P; de A Bernardes, T; Milane, P V G N; Paula, D P; Pires, C S S; Fontes, E M G

2013-02-01

Bt cotton plants expressing Cry1Ac protein have high specificity for the control of lepidopteran larvae. However, studies conducted in several countries have shown these plants have a differential impact on nontarget herbivores. The aim of this study was to compare the colonization rates and population abundance of the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae) and the boll weevil, Anthonomus grandis Boheman (Coleoptera: Curculionidae), in plots of Bt (Nuopal) and non-Bt cotton (Delta Opal) in an experimental field in Brasilia, DF, Brazil. No difference was observed in the preference and colonization by winged aphids to plants from the two treatments. There was no significant difference in abundance of wingless aphids or in the production of winged aphids between treatments. Apparently, the parameters that control factors such as fecundity, survival, and dispersal were similar on both Bt and non-Bt plants. Monitoring of plants for coccinellids, a specialist predator of aphids, and ants that act on the dispersal of aphids among plants showed no significant difference between Bt and non-Bt plants, supporting the inference above. Regarding the effect on boll weevil, there was also no significant difference between treatments in the total number of fruiting structures attacked in each plot, the percentage of fruiting structures attacked per plant or on the number of weevils emerging from fruits with boll weevil damage from egg-laying, when damaged fruit samples were held in the laboratory. Based on these results, we conclude that there is no impact of Bt cotton crop expressing Cry1Ac on the nontarget herbivores tested under field conditions.

Effect of ant attendance by Monomorium minimum (Buckley) (Hymenoptera: Formicidae) on predation and parasitism of the soybean aphid Aphis glycines Matsumura (Hemiptera: Aphididae).

PubMed

Herbert, John J; Horn, David J

2008-10-01

Ant attendance is known to affect the population dynamics of aphids and may increase or decrease aphid populations through stimulation, predation, or protection. In this study, we performed a series of laboratory experiments to examine the effects of ant attendance on populations of the soybean aphid Aphis glycines. Aphid colonies were exposed to the predators Harmonia axyridis (Coccinellidae) and Orius insidiosus (Anthocoridae) and a parasitoid Aphidius colemani (Aphidiidae) in the presence and absence of attending Monomorium minimum (Formicidae). We also tested for direct effects of ant attendance in the absence of natural enemies. Ants attending soybean aphid populations were observed harassing or killing O. insidiosus and H. axyridis. Attendance interfered with both predator species, resulting in reduced predation and an increase in aphid numbers up to 10-fold in the presence of ants. Ants were not observed directly interfering with the parasitoid A. colemani, but the number of parasitized aphids was higher in aphid colonies that were left unattended by ants.

Vat, an Amazing Gene Conferring Resistance to Aphids and Viruses They Carry: From Molecular Structure to Field Effects

PubMed Central

Boissot, Nathalie; Schoeny, Alexandra; Vanlerberghe-Masutti, Flavie

2016-01-01

We review half a century of research on Cucumis melo resistance to Aphis gossypii from molecular to field levels. The Vat gene is unique in conferring resistance to both A. gossypii and the viruses it transmits. This double phenotype is aphid clone-dependent and has been observed in 25 melon accessions, mostly from Asia. It is controlled by a cluster of genes including CC-NLR, which has been characterized in detail. Copy-number polymorphisms (for the whole gene and for a domain that stands out in the LLR region) and single-nucleotide polymorphisms have been identified in the Vat cluster. The role of these polymorphisms in plant/aphid interactions remains unclear. The Vat gene structure suggests a functioning with separate recognition and response phases. During the recognition phase, the VAT protein is thought to interact (likely indirectly) with an aphid effector introduced during cell puncture by the aphid. A few hours later, several miRNAs are upregulated in Vat plants. Peroxidase activity increases, and callose and lignin are deposited in the walls of the cells adjacent to the stylet path, disturbing aphid behavior. In aphids feeding on Vat plants, Piwi-interacting RNA-like sequences are abundant and the levels of other miRNAs are modified. At the plant level, resistance to aphids is quantitative (aphids escape the plant and display low rates of reproduction). Resistance to viruses is qualitative and local. Durability of NLR genes is highly variable. A. gossypii clones are adapted to Vat resistance, either by introducing a new effector that interferes with the deployment of plant defenses, or by adapting to the defenses it triggered. Viruses transmitted in a non-persistent manner cannot adapt to Vat resistance. At population level, Vat reduces aphid density and genetic diversity. The durability of Vat resistance to A. gossypii populations depends strongly on the agro-ecosystem, including, in particular, the presence of other cucurbit crops serving as

DNA barcoding reveals a mysterious high species diversity of conifer-feeding aphids in the mountains of southwest China

PubMed Central

Chen, Rui; Jiang, Li-Yun; Chen, Jing; Qiao, Ge-Xia

2016-01-01

The mountains of southwest China are one of the hot spots of biodiversity in the world. However, the high-altitude fauna that inhabit these mountains remain a mystery. In this study, the species diversity of the aphids of the genus Cinara from the high-altitude coniferous forests was first assessed, and then the processes and the mechanisms of speciation were discussed. Three hundreds and four aphid samples that contained 3040 individuals were collected during fourteen field surveys. The molecular clusters derived from the DNA barcodes were used to explore the species diversity. Notably, the aphid alpha-diversity was high, with as many as 94 candidate species, and furthermore, 86.2% of the species collected had not been previously recorded. The centers of aphid species richness corresponded to the distributional pattern of the diversity of the host conifer plant species. The divergence time revealed that following the uplift of the Qinghai-Tibetan Plateau during the Pleistocene, the changes in the climate, ecology and host habitats were likely the most important factors that drove the rapid process of evolutionary radiation in the aphids. Our findings revealed the high species diversity of the aphids with DNA barcoding. PMID:26838797

Proteomic Analysis of Aphid-Resistant and -Sensitive Rose (Rosa Hybrida) Cultivars at Two Developmental Stages.

PubMed

Muneer, Sowbiya; Jeong, Hai Kyoung; Park, Yoo Gyeong; Jeong, Byoung Ryong

2018-05-25

The rose is one the most commercially grown and costly ornamental plants because of its aesthetic beauty and aroma. A large number of pests attack its buds, flowers, leaves, and stem at every growing stage due to its high sugar content. The most common pest on roses are aphids which are considered to be the major cause for product loss. Aphid infestations lead to major changes in rose plants, such as large and irregular holes in petals, intact leaves and devouring tissues. It is hypothesized that different cut rose cultivars would have different levels of sensitivity or resistance to aphids, since different levels of infestation are observed in commercially cut rose production greenhouses. The present work compared four cut rose cultivars which were bred in Korea and were either resistant or sensitive to aphid infestation at different flower developmental stages. An integrative study was conducted using comprehensive proteome analyses. Proteins related to ubiquitin metabolism and the stress response were differentially expressed due to aphid infestation. The regulations and possible functions of identified proteins are presented in detail. The differential expressions of the identified proteins were validated by immunoblotting and blue native page. In addition, total sugar and carbohydrate content were also observed.

[Effects of reduced nitrogen application and soybean intercropping on nitrogen balance of sugarcane field].

PubMed

Liu, Yu; Zhang, Ying; Yang, Wen-ting; Li, Zhi-xian; Guan, Ao-mei

2015-03-01

A four-year (2010-2013) field experiment was carried out to explore the effects of three planting patterns (sugarcane, soybean monoculture and sugarcane-soybean 1:2 intercropping) with two nitrogen input levels (300 and 525 kg . hm-2) on soybean nitrogen fixation, sugarcane and soybean nitrogen accumulation, and ammonia volatilization and nitrogen leaching in sugarcane field. The results showed that the soybean nitrogen fixation efficiency (NFE) of sugarcane-soybean inter-cropping was lower than that of soybean monoculture. There was no significant difference in NFE among the treatments with the two nitrogen application rates. The nitrogen application rate and inter-cropping did not remarkably affect nitrogen accumulation of sugarcane and soybean. The ammonia volatilization of the reduced nitrogen input treatment was significantly lower than that of the conventional nitrogen input treatment. Furthermore, there was no significant difference in nitrogen leaching at different nitrogen input levels and among different planting patterns. The sugarcane field nitrogen balance analysis indicated that the nitrogen application rate dominated the nitrogen budget of sugarcane field. During the four-year experiment, all treatments leaved a nitrogen surplus (from 73.10 to 400.03 kg . hm-2) , except a nitrogen deficit of 66.22 kg . hm-2 in 2011 in the treatment of sugarcane monoculture with the reduced nitrogen application. The excessive nitrogen surplus might increase the risk of nitrogen pollution in the field. In conclusion, sugarcane-soybean intercropping with reduced nitrogen application is feasible to practice in consideration of enriching the soil fertility, reducing nitrogen pollution and saving production cost in sugarcane field.

Biological Control Outcomes Using the Generalist Aphid Predator Aphidoletes aphidimyza under Multi-Prey Conditions.

PubMed

Jandricic, Sarah E; Wraight, Stephen P; Gillespie, Dave R; Sanderson, John P

2016-12-14

The aphidophagous midge Aphidoletes aphidimyza (Diptera: Cecidomyiidae) is used in biological control programs against aphids in many crops. Short-term trials with this natural enemy demonstrated that that females prefer to oviposit among aphids colonizing the new growth of plants, leading to differential attack rates for aphid species that differ in their within-plant distributions. Thus, we hypothesized that biological control efficacy could be compromised when more than one aphid species is present. We further hypothesized that control outcomes may be different at different crop stages if aphid species shift their preferred feeding locations. Here, we used greenhouse trials to determine biological control outcomes using A. aphidimyza under multi-prey conditions and at different crop stages. At all plant stages, aphid species had a significant effect on the number of predator eggs laid. More eggs were found on M. persicae versus A. solani -infested plants, since M. persicae consistently colonized plant meristems across plant growth stages. This translated to higher numbers of predatory larvae on M. periscae -infested plants in two out of our three experiments, and more consistent control of this pest (78%-95% control across all stages of plant growth). In contrast, control of A. solani was inconsistent in the presence of M. persicae , with 36%-80% control achieved. An additional experiment demonstrated control of A. solani by A. aphidimyza was significantly greater in the absence of M. persicae than in its presence. Our study illustrates that suitability of a natural enemy for pest control may change over a crop cycle as the position of prey on the plant changes, and that prey preference based on within-plant prey location can negatively influence biological control programs in systems with pest complexes. Careful monitoring of the less-preferred pest and its relative position on the plant is suggested.

Lack of Detection of Bt Sugarcane Cry1Ab and NptII DNA and Proteins in Sugarcane Processing Products Including Raw Sugar

PubMed Central

Cheavegatti-Gianotto, Adriana; Gentile, Agustina; Oldemburgo, Danielle Angeloni; Merheb, Graciela do Amaral; Sereno, Maria Lorena; Lirette, Ron Peter; Ferreira, Thais Helena Silva; de Oliveira, Wladecir Salles

2018-01-01

Brazil is the largest sugarcane producer and the main sugar exporter in the world. The industrial processes applied by Brazilian mills are very efficient in producing highly purified sugar and ethanol. Literature presents evidence of lack of DNA/protein in these products, regardless of the nature of sugarcane used as raw material. Recently CTNBio, the Brazilian biosafety authority, has approved the first biotechnology-derived sugarcane variety for cultivation, event CTC175-A, which expresses the Cry1Ab protein to control the sugarcane borer (Diatraea saccharalis). The event also expresses neomycin-phosphotransferase type II (NptII) protein used as selectable marker during the transformation process. Because of the high purity of sugar and ethanol produced from genetically modified sugarcane, these end-products should potentially be classified as “pure substances, chemically defined,” by Brazilian Biosafety Law No. 11.105. If this classification is to be adopted, these substances are not considered as “GMO derivatives” and fall out of the scope of Law No. 11.105. In order to assess sugar composition and quality, we evaluate Cry1Ab and NptII expression in several sugarcane tissues and in several fractions from laboratory-scale processing of event CTC175-A for the presence of these heterologous proteins as well as for the presence of traces of recombinant DNA. The results of these studies show that CTC175-A presents high expression of Cry1Ab in leaves and barely detectable expression of heterologous proteins in stalks. We also evaluated the presence of ribulose-1,5-bisphosphate carboxylase/oxygenase protein and DNA in the fractions of the industrial processing of conventional Brazilian sugarcane cultivars. Results from both laboratory and industrial processing were concordant, demonstrating that DNA and protein are not detected in the clarified juice and downstream processed fractions, including ethanol and raw sugar, indicating that protein and DNA are

Bacterial Communities Associated with Host-Adapted Populations of Pea Aphids Revealed by Deep Sequencing of 16S Ribosomal DNA

PubMed Central

Gauthier, Jean-Pierre; Outreman, Yannick; Mieuzet, Lucie; Simon, Jean-Christophe

2015-01-01

Associations between microbes and animals are ubiquitous and hosts may benefit from harbouring microbial communities through improved resource exploitation or resistance to environmental stress. The pea aphid, Acyrthosiphon pisum, is the host of heritable bacterial symbionts, including the obligate endosymbiont Buchnera aphidicola and several facultative symbionts. While obligate symbionts supply aphids with key nutrients, facultative symbionts influence their hosts in many ways such as protection against natural enemies, heat tolerance, color change and reproduction alteration. The pea aphid also encompasses multiple plant-specialized biotypes, each adapted to one or a few legume species. Facultative symbiont communities differ strongly between biotypes, although bacterial involvement in plant specialization is uncertain. Here, we analyse the diversity of bacterial communities associated with nine biotypes of the pea aphid complex using amplicon pyrosequencing of 16S rRNA genes. Combined clustering and phylogenetic analyses of 16S sequences allowed identifying 21 bacterial OTUs (Operational Taxonomic Unit). More than 98% of the sequencing reads were assigned to known pea aphid symbionts. The presence of Wolbachia was confirmed in A. pisum while Erwinia and Pantoea, two gut associates, were detected in multiple samples. The diversity of bacterial communities harboured by pea aphid biotypes was very low, ranging from 3 to 11 OTUs across samples. Bacterial communities differed more between than within biotypes but this difference did not correlate with the genetic divergence between biotypes. Altogether, these results confirm that the aphid microbiota is dominated by a few heritable symbionts and that plant specialization is an important structuring factor of bacterial communities associated with the pea aphid complex. However, since we examined the microbiota of aphid samples kept a few generations in controlled conditions, it may be that bacterial diversity was

Yellow Fever

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Landscape Context Affects Aphid Parasitism by Lysiphlebus testaceipes (Hymenoptera: Aphidiinae) in Wheat Fields.

PubMed

Elliott, Norman C; Brewer, Michael J; Giles, Kristopher L

2018-04-12

Winter wheat is Oklahoma's most widely grown crop, and is planted during September and October, grows from fall through spring, and is harvested in June. Winter wheat fields are typically interspersed in a mosaic of habitats in other uses, and we hypothesized that the spatial and temporal composition and configuration of landscape elements, which contribute to agroecosystem diversity also influence biological control of common aphid pests. The parasitoid Lysiphlebus testaceipes (Cresson; Hymenoptera: Aphidiinae) is highly effective at reducing aphid populations in wheat in Oklahoma, and though a great deal is known about the biology and ecology of L. testaceipes, there are gaps in knowledge that limit predicting when and where it will be effective at controlling aphid infestations in wheat. Our objective was to determine the influence of landscape structure on parasitism of cereal aphids by L. testaceipes in wheat fields early in the growing season when aphid and parasitoid colonization occurs and later in the growing season when aphid and parasitoid populations are established in wheat fields. Seventy fields were studied during the three growing seasons. Significant correlations between parasitism by L. testaceipes and landscape variables existed for patch density, fractal dimension, Shannon's patch diversity index, percent wheat, percent summer crops, and percent wooded land. Correlations between parasitism and landscape variables were generally greatest at a 3.2 km radius surrounding the wheat field. Correlations between parasitism and landscape variables that would be expected to increase with increasing landscape diversity were usually positive. Subsequent regression models for L. testaceipes parasitism in wheat fields in autumn and spring showed that landscape variables influenced parasitism and indicated that parasitism increased with increasing landscape diversity. Overall, results indicate that L. testaceipes utilizes multiple habitats throughout the year

A protein from the salivary glands of the pea aphid, Acyrthosiphon pisum, is essential in feeding on a host plant

USDA-ARS?s Scientific Manuscript database

In feeding, aphids inject saliva into plant tissues, gaining access to phloem sap and eliciting (and sometimes overcoming) plant responses. We are examining the involvement, in this aphid-plant interaction, of individual aphid proteins and enzymes, as identified in a salivary gland cDNA library. Her...

Identificatoin and confirmation of resistance against soybean aphid (Aphis glycines) in eight wild soybean lines

USDA-ARS?s Scientific Manuscript database

The development and use of aphid-resistant soybean (Glycine max) cultivars has been complicated by the presence of multiple virulent biotypes of the soybean aphid (SA, Aphis glycines Matsumura). Ultimately, a variety of unique resistance sources may be needed to develop cultivars with a broad spectr...

Genetic diversity of viruses causing mosaic in Louisiana sugarcane

USDA-ARS?s Scientific Manuscript database

Mosaic caused by Sugarcane mosaic virus (SCMV) contributed to the near collapse of Louisiana’s sugarcane industry in the early 20th Century. By the 1950s, the cultivation of resistant cultivars eliminated mosaic as a major disease problem; however, new strains arose among previously resistant cultiv...

Repeatability of Sugarcane Selection on Sand and Organic Soils

USDA-ARS?s Scientific Manuscript database

The Canal Point (CP) Sugarcane Cultivar Development Program (a cooperative program between the USDA-ARS, the University of Florida and the Florida Sugarcane League) has been more successful at breeding for cultivars adapted to organic soils (muck) than for those adapted to sand soils. Currently, onl...

Expression Profiling of Selected Glutathione Transferase Genes in Zea mays (L.) Seedlings Infested with Cereal Aphids

PubMed Central

Sytykiewicz, Hubert; Chrzanowski, Grzegorz; Czerniewicz, Paweł; Sprawka, Iwona; Łukasik, Iwona; Goławska, Sylwia; Sempruch, Cezary

2014-01-01

The purpose of this report was to evaluate the expression patterns of selected glutathione transferase genes (gst1, gst18, gst23 and gst24) in the tissues of two maize (Zea mays L.) varieties (relatively resistant Ambrozja and susceptible Tasty Sweet) that were colonized with oligophagous bird cherry-oat aphid (Rhopalosiphum padi L.) or monophagous grain aphid (Sitobion avenae L.). Simultaneously, insect-triggered generation of superoxide anion radicals (O2 •−) in infested Z. mays plants was monitored. Quantified parameters were measured at 1, 2, 4, 8, 24, 48 and 72 h post-initial aphid infestation (hpi) in relation to the non-infested control seedlings. Significant increases in gst transcript amounts were recorded in aphid-stressed plants in comparison to the control seedlings. Maximal enhancement in the expression of the gst genes in aphid-attacked maize plants was found at 8 hpi (gst23) or 24 hpi (gst1, gst18 and gst24) compared to the control. Investigated Z. mays cultivars formed excessive superoxide anion radicals in response to insect treatments, and the highest overproduction of O2 •− was noted 4 or 8 h after infestation, depending on the aphid treatment and maize genotype. Importantly, the Ambrozja variety could be characterized as having more profound increments in the levels of gst transcript abundance and O2 •− generation in comparison with the Tasty Sweet genotype. PMID:25365518

Study of Sugarcane Pieces as Yeast Supports for Ethanol Production from Sugarcane Juice and Molasses Using Newly Isolated Yeast from Toddy Sap

PubMed Central

Satyanarayana, Botcha; Balakrishnan, Kesavapillai; Raghava Rao, Tamanam; Seshagiri Rao, Gudapaty

2012-01-01

A repeated batch fermentation system was used to produce ethanol using Saccharomyces cerevisiae strain (NCIM 3640) immobilized on sugarcane (Saccharum officinarum L.) pieces. For comparison free cells were also used to produce ethanol by repeated batch fermentation. Scanning electron microscopy evidently showed that cell immobilization resulted in firm adsorption of the yeast cells within subsurface cavities, capillary flow through the vessels of the vascular bundle structure, and attachment of the yeast to the surface of the sugarcane pieces. Repeated batch fermentations using sugarcane supported biocatalyst were successfully carried out for at least ten times without any significant loss in ethanol production from sugarcane juice and molasses. The number of cells attached to the support increased during the fermentation process, and fewer yeast cells leaked into fermentation broth. Ethanol concentrations (about 72.65~76.28 g/L in an average value) and ethanol productivities (about 2.27~2.36 g/L/hr in an average value) were high and stable, and residual sugar concentrations were low in all fermentations (0.9~3.25 g/L) with conversions ranging from 98.03~99.43%, showing efficiency 91.57~95.43 and operational stability of biocatalyst for ethanol fermentation. The results of the work pertaining to the use of sugarcane as immobilized yeast support could be promising for industrial fermentations. PMID:22783132

Analogous pleiotropic effects of insecticide resistance genotypes in peach-potato aphids and houseflies.

PubMed

Foster, S P; Young, S; Williamson, M S; Duce, I; Denholm, I; Devine, G J

2003-08-01

We show that single-point mutations conferring target-site resistance (kdr) to pyrethroids and DDT in aphids and houseflies, and gene amplification conferring metabolic resistance (carboxylesterase) to organophosphates and carbamates in aphids, can have deleterious pleiotropic effects on fitness. Behavioural studies on peach-potato aphids showed that a reduced response to alarm pheromone was associated with both gene amplification and the kdr target-site mutation. In this species, gene amplification was also associated with a decreased propensity to move from senescing leaves to fresh leaves at low temperature. Housefly genotypes possessing the identical kdr mutation were also shown to exhibit behavioural differences in comparison with susceptible insects. In this species, resistant individuals showed no positional preference along a temperature gradient while susceptible genotypes exhibited a strong preference for warmer temperatures.

Climate change and sugarcane expansion increase Hantavirus infection risk.

PubMed

Prist, Paula Ribeiro; Uriarte, María; Fernandes, Katia; Metzger, Jean Paul

2017-07-01

Hantavirus Cardiopulmonary Syndrome (HCPS) is a disease caused by Hantavirus, which is highly virulent for humans. High temperatures and conversion of native vegetation to agriculture, particularly sugarcane cultivation can alter abundance of rodent generalist species that serve as the principal reservoir host for HCPS, but our understanding of the compound effects of land use and climate on HCPS incidence remains limited, particularly in tropical regions. Here we rely on a Bayesian model to fill this research gap and to predict the effects of sugarcane expansion and expected changes in temperature on Hantavirus infection risk in the state of São Paulo, Brazil. The sugarcane expansion scenario was based on historical data between 2000 and 2010 combined with an agro-environment zoning guideline for the sugar and ethanol industry. Future evolution of temperature anomalies was derived using 32 general circulation models from scenarios RCP4.5 and RCP8.5 (Representative greenhouse gases Concentration Pathways adopted by IPCC). Currently, the state of São Paulo has an average Hantavirus risk of 1.3%, with 6% of the 645 municipalities of the state being classified as high risk (HCPS risk ≥ 5%). Our results indicate that sugarcane expansion alone will increase average HCPS risk to 1.5%, placing 20% more people at HCPS risk. Temperature anomalies alone increase HCPS risk even more (1.6% for RCP4.5 and 1.7%, for RCP8.5), and place 31% and 34% more people at risk. Combined sugarcane and temperature increases led to the same predictions as scenarios that only included temperature. Our results demonstrate that climate change effects are likely to be more severe than those from sugarcane expansion. Forecasting disease is critical for the timely and efficient planning of operational control programs that can address the expected effects of sugarcane expansion and climate change on HCPS infection risk. The predicted spatial location of HCPS infection risks obtained here can be

Climate change and sugarcane expansion increase Hantavirus infection risk

PubMed Central

Uriarte, María; Fernandes, Katia; Metzger, Jean Paul

2017-01-01

Hantavirus Cardiopulmonary Syndrome (HCPS) is a disease caused by Hantavirus, which is highly virulent for humans. High temperatures and conversion of native vegetation to agriculture, particularly sugarcane cultivation can alter abundance of rodent generalist species that serve as the principal reservoir host for HCPS, but our understanding of the compound effects of land use and climate on HCPS incidence remains limited, particularly in tropical regions. Here we rely on a Bayesian model to fill this research gap and to predict the effects of sugarcane expansion and expected changes in temperature on Hantavirus infection risk in the state of São Paulo, Brazil. The sugarcane expansion scenario was based on historical data between 2000 and 2010 combined with an agro-environment zoning guideline for the sugar and ethanol industry. Future evolution of temperature anomalies was derived using 32 general circulation models from scenarios RCP4.5 and RCP8.5 (Representative greenhouse gases Concentration Pathways adopted by IPCC). Currently, the state of São Paulo has an average Hantavirus risk of 1.3%, with 6% of the 645 municipalities of the state being classified as high risk (HCPS risk ≥ 5%). Our results indicate that sugarcane expansion alone will increase average HCPS risk to 1.5%, placing 20% more people at HCPS risk. Temperature anomalies alone increase HCPS risk even more (1.6% for RCP4.5 and 1.7%, for RCP8.5), and place 31% and 34% more people at risk. Combined sugarcane and temperature increases led to the same predictions as scenarios that only included temperature. Our results demonstrate that climate change effects are likely to be more severe than those from sugarcane expansion. Forecasting disease is critical for the timely and efficient planning of operational control programs that can address the expected effects of sugarcane expansion and climate change on HCPS infection risk. The predicted spatial location of HCPS infection risks obtained here can be

Resistance of Wheat Accessions to the English Grain Aphid Sitobion avenae

PubMed Central

Hu, Xiang-Shun; Liu, Ying-Jie; Wang, Yu-Han; Wang, Zhe; Yu, Xin-lin; Wang, Bo; Zhang, Gai-Sheng; Liu, Xiao-Feng; Hu, Zu-Qing; Zhao, Hui-Yan; Liu, Tong-Xian

2016-01-01

The English grain aphid, Sitobion avenae, is a major pest species of wheat crops; however, certain varieties may have stronger resistance to infestation than others. Here, we investigated 3 classical resistance mechanisms (antixenosis, antibiosis, and tolerance) by 14 wheat varieties/lines to S. avenae under laboratory and field conditions. Under laboratory conditions, alatae given the choice between 2 wheat varieties, strongly discriminated against certain varieties. Specifically, the ‘Amigo’ variety had the lowest palatability to S. avenae alatae of all varieties. ‘Tm’ (Triticum monococcum), ‘Astron,’ ‘Xanthus,’ ‘Ww2730,’ and ‘Batis’ varieties also had lower palatability than other varieties. Thus, these accessions may use antibiosis as the resistant mechanism. In contrast, under field conditions, there were no significant differences in the number of alatae detected on the 14 wheat varieties. One synthetic line (98-10-30, a cross between of Triticum aestivum (var. Chris) and Triticum turgidum (var. durum) hybridization) had low aphid numbers but high yield loss, indicating that it has high antibiosis, but poor tolerance. In comparison, ‘Amigo,’ ‘Xiaoyan22,’ and some ‘186Tm’ samples had high aphid numbers but low yield loss rates, indicating they have low antibiosis, but good tolerance. Aphid population size and wheat yield loss rates greatly varied in different fields and years for ‘98-10-35,’ ‘Xiaoyan22,’ ‘Tp,’ ‘Tam200,’ ‘PI high,’ and other ‘186Tm’ samples, which were hybrid offspring of T. aestivum and wheat related species. Thus, these germplasm should be considered for use in future studies. Overall, S. avenae is best adapted to ‘Xinong1376,’ because it was the most palatable variety, with the greatest yield loss rates of all 14 wheat varieties. However, individual varieties/lines influenced aphid populations differently in different years. Therefore, we strongly recommend a combination of

Proteomic analysis of a compatible interaction between sugarcane and Sporisorium scitamineum.

PubMed

Barnabas, Leonard; Ashwin, N M R; Kaverinathan, K; Trentin, Anna Rita; Pivato, Micaela; Sundar, A Ramesh; Malathi, P; Viswanathan, R; Rosana, O B; Neethukrishna, K; Carletti, Paolo; Arrigoni, Giorgio; Masi, Antonio; Agrawal, Ganesh Kumar; Rakwal, Randeep

2016-04-01

Smut caused by Sporisorium scitamineum is one of the important diseases of sugarcane with global significance. Despite the intriguing nature of sugarcane, S. scitamineum interaction, several pertinent aspects remain unexplored. This study investigates the proteome level alterations occurring in the meristem of a S. scitamineum infected susceptible sugarcane cultivar at whip emergence stage. Differentially abundant proteins were identified by 2DE coupled with MALDI-TOF/TOF-MS. Comprehensively, 53 sugarcane proteins identified were related to defence, stress, metabolism, protein folding, energy, and cell division; in addition, a putative effector of S. scitamineum, chorismate mutase, was identified. Transcript expression vis-à-vis the activity of phenylalanine ammonia lyase was relatively higher in the infected meristem. Abundance of seven candidate proteins in 2D gel profiles was in correlation with its corresponding transcript expression levels as validated by qRT-PCR. Furthermore, this study has opened up new perspectives on the interaction between sugarcane and S. scitamineum. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Safeguarding world wheat and barley production against Russian wheat aphid: An international pre-breeding initiative

USDA-ARS?s Scientific Manuscript database

The Russian wheat aphid (RWA), Diuraphis noxia, is one of the most damaging insect pests of wheat and barley throughout the World. This aphid, although is not yet present in Australia, is extremely damaging with up to 70% yield loses in wheat and barley producing lands, causing significant financia...

Isolated and Community Contexts Produce Distinct Responses by Host Plants to the Presence of Ant-Aphid Interaction: Plant Productivity and Seed Viability.

PubMed

Canedo-Júnior, Ernesto Oliveira; Santiago, Graziele Silva; Zurlo, Luana Fonseca; Ribas, Carla Rodrigues; Carvalho, Rafaela Pereira; Alves, Guilherme Pereira; Carvalho, Mariana Comanucci Silva; Souza, Brígida

2017-01-01

Ant-aphid interactions may affect host plants in several ways, however, most studies measure only the amount of fruit and seed produced, and do not test seed viability. Therefore, the aim of this study was to assess the effects of the presence of ant-aphid interactions upon host plant productivity and seed viability in two different contexts: isolated and within an arthropod community. For this purpose we tested the hypothesis that in both isolated and community contexts, the presence of an ant-aphid interaction will have a positive effect on fruit and seed production, seed biomass and rate of seed germination, and a negative effect on abnormal seedling rates, in comparison to plants without ants. We performed a field mesocosm experiment containing five treatments: Ant-aphid, Aphid, Community, Ant-free community and Control. We counted fruits and seeds produced by each treatment, and conducted experiments for seed biomass and germinability. We found that in the community context the presence of an ant-aphid interaction negatively affected fruit and seed production. We think this may be because aphid attendance by tending-ants promotes aphid damage to the host plant, but without an affect on seed weight and viability. On the other hand, when isolated, the presence of an ant-aphid interaction positively affected fruit and seed production. These positive effects are related to the cleaning services offered to aphids by tending-ants, which prevent the development of saprophytic fungi on the surface of leaves, which would cause a decrease in photosynthetic rates. Our study is important because we evaluated some parameters of plant fitness that have not been addressed very well by other studies involving the effects of ant-aphid interactions mainly on plants with short life cycles. Lastly, our context dependent approach sheds new light on how ecological interactions can vary among different methods of crop management.

Isolated and Community Contexts Produce Distinct Responses by Host Plants to the Presence of Ant-Aphid Interaction: Plant Productivity and Seed Viability

PubMed Central

Santiago, Graziele Silva; Zurlo, Luana Fonseca; Ribas, Carla Rodrigues; Carvalho, Rafaela Pereira; Alves, Guilherme Pereira; Carvalho, Mariana Comanucci Silva; Souza, Brígida

2017-01-01

Ant-aphid interactions may affect host plants in several ways, however, most studies measure only the amount of fruit and seed produced, and do not test seed viability. Therefore, the aim of this study was to assess the effects of the presence of ant-aphid interactions upon host plant productivity and seed viability in two different contexts: isolated and within an arthropod community. For this purpose we tested the hypothesis that in both isolated and community contexts, the presence of an ant-aphid interaction will have a positive effect on fruit and seed production, seed biomass and rate of seed germination, and a negative effect on abnormal seedling rates, in comparison to plants without ants. We performed a field mesocosm experiment containing five treatments: Ant-aphid, Aphid, Community, Ant-free community and Control. We counted fruits and seeds produced by each treatment, and conducted experiments for seed biomass and germinability. We found that in the community context the presence of an ant-aphid interaction negatively affected fruit and seed production. We think this may be because aphid attendance by tending-ants promotes aphid damage to the host plant, but without an affect on seed weight and viability. On the other hand, when isolated, the presence of an ant-aphid interaction positively affected fruit and seed production. These positive effects are related to the cleaning services offered to aphids by tending-ants, which prevent the development of saprophytic fungi on the surface of leaves, which would cause a decrease in photosynthetic rates. Our study is important because we evaluated some parameters of plant fitness that have not been addressed very well by other studies involving the effects of ant-aphid interactions mainly on plants with short life cycles. Lastly, our context dependent approach sheds new light on how ecological interactions can vary among different methods of crop management. PMID:28141849

Deciphering the role of NADPH oxidase in complex interactions between maize (Zea mays L.) genotypes and cereal aphids.

PubMed

Sytykiewicz, Hubert

2016-07-22

Plant NADPH oxidases (NOXs) encompass a group of membrane-bound enzymes participating in formation of reactive oxygen species (ROS) under physiological conditions as well as in response to environmental stressors. The purpose of the survey was to unveil the role of NADPH oxidase in pro-oxidative responses of maize (Zea mays L.) seedling leaves exposed to cereal aphids' infestation. The impact of apteral females of bird cherry-oat aphid (Rhopalosiphum padi L.) and grain aphid (Sitobion avenae F.) feeding on expression levels of all four NADPH oxidase genes (rbohA, rbohB, rbohC, rbohD) and total activity of NOX enzyme in maize plants were investigated. In addition, inhibitory effect of diphenylene iodonium (DPI) pre-treatment on NOX activity and hydrogen peroxide content in aphid-stressed maize seedlings was studied. Leaf infestation biotests were accomplished on 14-day-old seedlings representing two aphid-resistant varieties (Ambrozja and Waza) and two aphid-susceptible ones (Tasty Sweet and Złota Karłowa). Insects' attack led to profound upregulation of rbohA and rbohD genes in tested host plants, lower elevations were noted in level of rbohB mRNA, whereas abundance of rbohC transcript was not significantly altered. It was uncovered aphid-induced enhancement of NOX activity in examined plants. Higher increases in expression of all investigated rboh genes and activity of NADPH oxidase occurred in tissues of more resistant maize cultivars than in susceptible ones. Furthermore, DPI treatment resulted in strong reduction of NOX activity and H2O2 accumulation in aphid-infested Z. mays plants, thus evidencing circumstantial role of the enzyme in insect-elicited ROS generation. Copyright © 2016 Elsevier Inc. All rights reserved.

Characterization of Arabidopsis Transcriptional Responses to Different Aphid Species Reveals Genes that Contribute to Host Susceptibility and Non-host Resistance

PubMed Central

Jaouannet, Maëlle; Morris, Jenny A.; Hedley, Peter E.; Bos, Jorunn I. B.

2015-01-01

Aphids are economically important pests that display exceptional variation in host range. The determinants of diverse aphid host ranges are not well understood, but it is likely that molecular interactions are involved. With significant progress being made towards understanding host responses upon aphid attack, the mechanisms underlying non-host resistance remain to be elucidated. Here, we investigated and compared Arabidopsis thaliana host and non-host responses to aphids at the transcriptional level using three different aphid species, Myzus persicae, Myzus cerasi and Rhopalosiphum pisum. Gene expression analyses revealed a high level of overlap in the overall gene expression changes during the host and non-host interactions with regards to the sets of genes differentially expressed and the direction of expression changes. Despite this overlap in transcriptional responses across interactions, there was a stronger repression of genes involved in metabolism and oxidative responses specifically during the host interaction with M. persicae. In addition, we identified a set of genes with opposite gene expression patterns during the host versus non-host interactions. Aphid performance assays on Arabidopsis mutants that were selected based on our transcriptome analyses identified novel genes contributing to host susceptibility, host defences during interactions with M. persicae as well to non-host resistance against R. padi. Understanding how plants respond to aphid species that differ in their ability to infest plant species, and identifying the genes and signaling pathways involved, is essential for the development of novel and durable aphid control in crop plants. PMID:25993686

Multitemporal Observations of Sugarcane by TerraSAR-X Images

PubMed Central

Baghdadi, Nicolas; Cresson, Rémi; Todoroff, Pierre; Moinet, Soizic

2010-01-01

The objective of this study is to investigate the potential of TerraSAR-X (X-band) in monitoring sugarcane growth on Reunion Island (located in the Indian Ocean). Multi-temporal TerraSAR data acquired at various incidence angles (17°, 31°, 37°, 47°, 58°) and polarizations (HH, HV, VV) were analyzed in order to study the behaviour of SAR (synthetic aperture radar) signal as a function of sugarcane height and NDVI (Normalized Difference Vegetation Index). The potential of TerraSAR for mapping the sugarcane harvest was also studied. Radar signal increased quickly with crop height until a threshold height, which depended on polarization and incidence angle. Beyond this threshold, the signal increased only slightly, remained constant, or even decreased. The threshold height is slightly higher with cross polarization and higher incidence angles (47° in comparison with 17° and 31°). Results also showed that the co-polarizations channels (HH and VV) were well correlated. High correlation between SAR signal and NDVI calculated from SPOT-4/5 images was observed. TerraSAR data showed that after strong rains the soil contribution to the backscattering of sugarcane fields can be important for canes with heights of terminal visible dewlap (htvd) less than 50 cm (total cane heights around 155 cm). This increase in radar signal after strong rains could involve an ambiguity between young and mature canes. Indeed, the radar signal on TerraSAR images acquired in wet soil conditions could be of the same order for fields recently harvested and mature sugarcane fields, making difficult the detection of cuts. Finally, TerraSAR data at high spatial resolution were shown to be useful for monitoring sugarcane harvest when the fields are of small size or when the cut is spread out in time. The comparison between incidence angles of 17°, 37° and 58° shows that 37° is more suitable to monitor the sugarcane harvest. The cut is easily detectable on TerraSAR images for data acquired

Nucleotide sequence and phylogenetic analysis of Cucurbit yellow stunting disorder virus RNA 2.

PubMed

Livieratos, Ioannis C; Coutts, Robert H A

2002-06-01

The complete nucleotide sequence of Cucurbit yellow stunting disorder virus (CYSDV) RNA 2, a whitefly (Bemisia tabaci)-transmitted closterovirus with a bi-partite genome, is reported. CYSDV RNA 2 is 7,281 nucleotides long and contains the closterovirus hallmark gene array with a similar arrangement to the prototype member of the genus Crinivirus, Lettuce infectious yellows virus (LIYV). CYSDV RNA 2 contains open reading frames (ORFs) potentially encoding in a 5' to 3' direction for proteins of 5 kDa (ORF 1; hydrophobic protein), 62 kDa (ORF 2; heat shock protein 70 homolog, HSP70h), 59 kDa (ORF 3; protein of unknown function), 9 kDa (ORF 4; protein of unknown function), 28.5 kDa (ORF 5; coat protein, CP), 53 kDa (ORF 6; coat protein minor, CPm), and 26.5 kDa (ORF 7; protein of unknown function). Pairwise comparisons of CYSDV RNA 2-encoded proteins (HSP70h, p59 and CPm) among the closteroviruses showed that CYSDV is closely related to LIYV. Phylogenetic analysis based on the amino acid sequence of the HSP70h, indicated that CYSDV clusters with other members of the genus Crinivirus, and it is related to Little cherry virus-1 (LChV-1), but is distinct from the aphid- or mealybug-transmitted closteroviruses.

Sugarcane Responses to Water-Table Depth and Periodic Flood

USDA-ARS?s Scientific Manuscript database

Sugarcane (Saccharum spp.) is routinely exposed to periodic floods and shallow water tables in Florida’s Everglades Agricultural Area (EAA). The purpose of this study was to examine the yields and juice quality of four sugarcane cultivars (CP 88-1762, CP 89-2143, CP 89-2376, and CP 96-1252) maintain...

Spatial and temporal spread of Citrus tristeza virus and its aphid vectors in the North western area of Morocco.

PubMed

Elhaddad, Abdesslam; ElAmrani, Amal; Fereres, Alberto; Moreno, Aranzazu

2016-12-01

First report of Citrus tristeza virus (CTV,Closterovirus) in Morocco datesback to 1961 in collections of citrus varieties. An exhaustive survey of citrus in the north of the country in 2009 revealed that CTV was spread all over the citrus production area. We attempted to evaluate the relative contribution of different aphid species in the spread of CTV disease in a Citrus reticulata orchard at the Loukkous region during 2 years (2012 and 2013). The overall CTV incidence estimated in the experimental site increased from 17.8% in 2012 to 31.15% in 2013. The most abundant aphid species colonising clementine trees was Aphis spiraecola and A. gossypii. Both aphid species reached their maximum peaks during the spring season. The rate of viruliferous aphids, estimated by real-time RT-PCR of single aphid, revealed that 35.4% of winged A. gossypii and 28.8% of winged A. spiraecola were viruliferous, confirming a high inoculum pressure in the area surrounding the experimental site. The aphid species Toxoptera citricida, which is able to transmit the aggressive isolates of CTV, was not found in the Loukkous region. The study of the spatial distribution of the CTV showed that in general, the disease was randomly distributed in the field. Overall, the results seem to indicate that A. spiraecola may be considered as the major aphid species contributing to CTV spread in our experimental conditions. The prevalence of mild strains in the region and the high level of aphid flight activity could explain the rapid evolution of CTV incidence in the experimental area. © 2015 Institute of Zoology, Chinese Academy of Sciences.

Expression of the Galanthus nivalis agglutinin (GNA) gene in transgenic potato plants confers resistance to aphids.

PubMed

Mi, Xiaoxiao; Liu, Xue; Yan, Haolu; Liang, Lina; Zhou, Xiangyan; Yang, Jiangwei; Si, Huaijun; Zhang, Ning

2017-01-01

Aphids, the largest group of sap-sucking pests, cause significant yield losses in agricultural crops worldwide every year. The massive use of pesticides to combat this pest causes severe damage to the environment, putting in risk the human health. In this study, transgenic potato plants expressing Galanthus nivalis agglutinin (GNA) gene were developed using CaMV 35S and ST-LS1 promoters generating six transgenic lines (35S1-35S3 and ST1-ST3 corresponding to the first and second promoter, respectively). Quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated that the GNA gene was expressed in leaves, stems and roots of transgenic plants under the control of the CaMV 35S promoter, while it was only expressed in leaves and stems under the control of the ST-LS1 promoter. The levels of aphid mortality after 5 days of the inoculation in the assessed transgenic lines ranged from 20 to 53.3%. The range of the aphid population in transgenic plants 15 days after inoculation was between 17.0±1.43 (ST2) and 36.6±0.99 (35S3) aphids per plant, which corresponds to 24.9-53.5% of the aphid population in non-transformed plants. The results of our study suggest that GNA expressed in transgenic potato plants confers a potential tolerance to aphid attack, which appears to be an alternative against the use of pesticides in the future. Copyright © 2016 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Effect of foliar application of glyphosate and cobalt on sugarcane yields and quality

USDA-ARS?s Scientific Manuscript database

Sugarcane is one of the principal crops of the world, and is used in the production of sugar, alcohol and clean energy. In many sugarcane producing regions of the world selected herbicides, insecticides and fungicides are being evaluated for their potential bioactivator effects on sugarcane yields. ...

Neozygites osornensis sp. nov., a fungal species causing mortality to the cypress aphid Cinara cupressi in Chile.

PubMed

Retamal, Cristian Montalva; Barta, Marek; Pérez, Eladio Rojas; Flores, Eduardo Valenzuela

2013-01-01

An entomophthoralean fungus causing epizootics in populations of the cypress aphid, Cinara cupressi Buckton, in Chile is described as a new species, Neozygites osornensis Montalva et Barta. The aphid pathogen is described based on morphological characters. An exhaustive description, illustrations and a comparison with closely related species are provided. The fungus differs from similar Neozygites species by smaller hyphal bodies, nuclei, primary conidia, capilliconidia and capilliphores and by noticeably different shape of capilliconidia. A key to aphid-pathogenic species of Neozygites is also included.

Status of Imported and Native Predators of the Balsam Woolly Aphid on Mt. Mitchell, North Carolina

Treesearch

Gerhard F. Fedde

1972-01-01

On the Mt. Mitchell area during the summer of 1968, 20 stands of Fraser fir, Abies fraseri (Pursh) Poir., infested by the balsam woolly aphid, Adelges piceae (Ratzeburg), were examined for native and previously imported predators of the aphid. Laricobius erichsonii Bosenhauer (Coleoptera: Derodontidae) was...

Nutritional and productive performance of dairy cows fed corn silage or sugarcane silage with or without additives.

PubMed

de Andrade, Felipe Leite; Rodrigues, João Paulo Pacheco; Detmann, Edenio; Valadares Filho, Sebastião de Campos; Castro, Marcelo Messias Duarte; Trece, Aline Souza; Silva, Tadeu Eder; Fischer, Vivian; Weiss, Kirsten; Marcondes, Marcos Inácio

2016-04-01

The objective of this study was to compare the intake, digestibility, and performance of dairy cows fed corn silage, fresh sugarcane, and sugarcane ensiled in three different forms. Twenty-five Holstein cows at 114 ± 12.6 days in milk (DIM) were used. A randomized block design was adopted, using an arrangement of repeated measures over time. The following treatments were tested: corn silage (CS); fresh sugarcane (FS); sugarcane silage without additives (SCS); sugarcane silage enriched with calcium oxide at 5 g/kg of forage (SCSc); and sugarcane silage enriched with Lactobacillus buchneri at 5 × 10(4) cfu/kg of forage (SCSb). The roughage to concentrate ratio was 60:40 for the CS diet and 40:60 for the sugarcane-based diets. The dry matter intake (DMI) as a function of body weight had a downward trend for the cows fed sugarcane silage, compared with those fed FS. The sugarcane silages had higher digestibilities of dry matter (DM), organic matter (OM), and neutral detergent fiber (NDFap), compared with FS. The use of L. buchneri or calcium oxide improved the diet's digestibility. The use of FS, sugarcane silage, or sugarcane silage with additives had no effects on milk and fat-corrected milk yield, compared to corn silage. Cows fed FS presented lower milk total solids content and had a downward trend for milk fat, compared with cows fed sugarcane-silage diets. Cows fed sugarcane silages produced milk with higher casein stability in the alcohol test than cows fed fresh-sugarcane diet. Sugarcane silage, with or without additives, did not reduce the intake of dairy cows, and the use of additives improved the fiber's digestibility.